Public-domain books

A First Book in Algebra

REDUCTION OF FRACTIONS

Excerpts

Equations

Problems

Exercise 42

  1. Exercise 42, problem 1

    $\frac{\displaystyle 15x^3y^2z}{\displaystyle 40x^2y^2z^2}$.

    Printed answer:
    • $\displaystyle \frac{3x}{8z}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes 3*x/(8*z)
  2. Exercise 42, problem 10

    $\displaystyle \frac{a^2xy-x^3y^3}{ax^2-x^3y}$

    Printed answer:
    • $\displaystyle \frac{y(a+xy)}{x}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes y*(a+x*y)/x
  3. Exercise 42, problem 11

    $\displaystyle \frac{a^4-b^4}{(a^2+2ab+b^2)(a^2+b^2)}$

    Printed answer:
    • $\displaystyle \frac{a-b}{a+b}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes (a-b)/(a+b)
  4. Exercise 42, problem 12

    $\displaystyle \frac{x^8 -y^8}{(x^4+y^4)(x^4-2x^2y^2+y^4)}$

    Printed answer:
    • $\displaystyle \frac{x^2+y^2}{x^2-y^2}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes (x**2+y**2)/(x**2-y**2)
  5. Exercise 42, problem 13

    $\displaystyle \frac{a^2x^2-16a^2}{ax^2+9ax+20a}$

    Printed answer:
    • $\displaystyle \frac{a(x - 4)}{x + 5}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes a*(x-4)/(x+5)
  6. Exercise 42, problem 14

    $\displaystyle \frac{a^4-14a^2-51}{a^4-2a^2-15}$

    Printed answer:
    • $\displaystyle \frac{a^2 - 17}{a^2 - 5}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes (a**2-17)/(a**2-5)
  7. Exercise 42, problem 15

    $\displaystyle \frac{3+4x+x^2}{6+5x+x^2}$

    Printed answer:
    • $\displaystyle \frac{1 + x}{2 + x}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes (1+x)/(2+x)
  8. Exercise 42, problem 16

    $\displaystyle \frac{a^2-a^2b^2}{(a-ab)^2}$

    Printed answer:
    • $\displaystyle \frac{1 + b}{1 - b}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes (1+b)/(1-b)
  9. Exercise 42, problem 17

    At two-thirds of a cent apiece, what $b$ apples cost?

    Printed answer:
    • $\displaystyle \frac{2}{3}b$, or $\displaystyle \frac{2b}{3}$ cts.

    unverified: no computed check settled this one (yet)

    How it was checked
    • other: not a kind the checker handles 2*b/3
  10. Exercise 42, problem 18

    James is $x$ times as old as George. If James is $a$ years old, how old is George?

    Printed answer:
    • $\displaystyle \frac{a}{x}$ years.

    verified: the printed answer passed a computed check

    How it was checked
    • solve: passes, with the problem read into an equation {G: a/x}
  11. Exercise 42, problem 2

    $\frac{\displaystyle 12x^5y^2z^3}{\displaystyle 30xy^3z^3}$.

    Printed answer:
    • $\displaystyle \frac{2x^4}{5y}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes 2*x**4/(5*y)
  12. Exercise 42, problem 3

    $\displaystyle \frac{x^2-7x+12}{x^3+x-20}$.

    Printed answer:
    • $\displaystyle \frac{x-3}{x+5}$.

    unverified: no computed check settled this one (yet)

    How it was checked
    • identity: the printed answer does not match the problem (x-3)/(x+5)
  13. Exercise 42, problem 4

    $\displaystyle \frac{x^2+9x+18}{x^2-2x-15}$.

    Printed answer:
    • $\displaystyle \frac{x+6}{x-5}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes (x+6)/(x-5)
  14. Exercise 42, problem 5

    $\displaystyle \frac{a^6+a^4}{a^4-1}$

    Printed answer:
    • $\displaystyle \frac{a^4}{a^2-1}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes a**4/(a**2-1)
  15. Exercise 42, problem 6

    $\displaystyle \frac{x^5-x^2}{x^6-1}$

    Printed answer:
    • $\displaystyle \frac{x^2}{x^3+1}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes x**2/(x**3+1)
  16. Exercise 42, problem 7

    $\displaystyle \frac{mx - ny + nx - my}{ax-2by+2bx-ay}$

    Printed answer:
    • $\displaystyle \frac{m+n}{a+2b}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes (m+n)/(a+2*b)
  17. Exercise 42, problem 8

    $\displaystyle \frac{ac-bd+ad-bc}{ax-2by+2ay-bx}$

    Printed answer:
    • $\displaystyle \frac{c+d}{x+2y}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes (c+d)/(x+2*y)
  18. Exercise 42, problem 9

    $\displaystyle \frac{ac^2d-a^3d^3}{a^3c+a^4d}$

    Printed answer:
    • $\displaystyle \frac{d(c-ad)}{a^2}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes d*(c-a*d)/a**2

Exercise 43

  1. Exercise 43, problem 1

    $ \displaystyle \frac{bx - cx + m}{x}$

    Printed answer:
    • $\displaystyle b-c+\frac{m}{x}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes b - c + m/x
  2. Exercise 43, problem 10

    $\displaystyle \frac{a^3 - b^3}{a + b}$

    Printed answer:
    • $\displaystyle a^2-ab+b^2-\frac{2b^3}{a+b}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes a**2 - a*b + b**2 - 2*b**3/(a + b)
  3. Exercise 43, problem 11

    $\displaystyle \frac{8a^3}{2a - 1}$

    Printed answer:
    • $\displaystyle 4a^2+2a+1+\frac{1}{2a-1}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes 4*a**2 + 2*a + 1 + 1/(2*a - 1)
  4. Exercise 43, problem 12

    $\displaystyle \frac{27 x^3}{3x + 1}$

    Printed answer:
    • $\displaystyle 9x^2-3x+1-\frac{1}{3x+1}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes 9*x**2 - 3*x + 1 - 1/(3*x + 1)
  5. Exercise 43, problem 13

    $\displaystyle \frac{3x^3 + 8x^2 + 2}{x^2 + 2x - 1}$

    Printed answer:
    • $\displaystyle 3x+2-\frac{x-4}{x^2+2x-1}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes 3*x + 2 - (x - 4)/(x**2 + 2*x - 1)
  6. Exercise 43, problem 14

    $\displaystyle \frac{2a^3 + 3a^2 + 10a - 4}{a^2 + 3a + 2}$

    Printed answer:
    • $\displaystyle 2a-3+\frac{15a+2}{a^2+3a+2}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes 2*a - 3 + (15*a + 2)/(a**2 + 3*a + 2)
  7. Exercise 43, problem 15

    $\displaystyle \frac{2a^4 + 6a^3 - 6a + 2}{a^2 +a - 1}$

    Printed answer:
    • $ 2a^2+4a-2$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes 2*a**2 + 4*a - 2
  8. Exercise 43, problem 16

    $\displaystyle \frac{3x^4 - 5x^3 + x - 1}{x^2 - x - 1}$

    Printed answer:
    • $3x^2-2x+1$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes 3*x**2 - 2*x + 1
  9. Exercise 43, problem 17

    $ \displaystyle x + y - \frac{xy}{x - y}$

    Printed answer:
    • $\displaystyle \frac{x^2-y^2-xy}{x-y}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes (x**2 - y**2 - x*y)/(x - y)
  10. Exercise 43, problem 18

    $\displaystyle a - b - \frac{2 ab}{a + b}$

    Printed answer:
    • $\displaystyle \frac{a^2-2ab-b^2}{a+b}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes (a**2 - 2*a*b - b**2)/(a + b)
  11. Exercise 43, problem 19

    $\displaystyle -c + d + \frac{c^3 + d^3}{c^2 + cd + d^2}$

    Printed answer:
    • $\displaystyle \frac{2d^3}{c^2+cd+d^2}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes 2*d**3/(c**2 + c*d + d**2)
  12. Exercise 43, problem 2

    $ \displaystyle \frac{mn + an + x}{n}$

    Printed answer:
    • $\displaystyle m+a+\frac{x}{n}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes m + a + x/n
  13. Exercise 43, problem 20

    $\displaystyle \frac{x^2y + xy^2}{x - y} + x^2 - y^2$

    Printed answer:
    • $\displaystyle \frac{x^3+y^3}{x-y}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes (x**3 + y**3)/(x - y)
  14. Exercise 43, problem 21

    $\displaystyle \frac{x+2}{3x - 1} - x - 2$

    Printed answer:
    • $\displaystyle \frac{4-4x-3x^2}{3x-1}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes (4 - 4*x - 3*x**2)/(3*x - 1)
  15. Exercise 43, problem 22

    $\displaystyle 2a - 1 - \frac{a-2}{a+3}$

    Printed answer:
    • $\displaystyle \frac{2a^2+4a-1}{a+3}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes (2*a**2 + 4*a - 1)/(a + 3)
  16. Exercise 43, problem 23

    $\displaystyle a^2 - 3a + 2 - \frac{a + 3}{2a^2 - 1}$

    Printed answer:
    • $\displaystyle \frac{2a^4-6a^3+3a^2+2a-5}{2a^2-1}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes (2*a**4 - 6*a**3 + 3*a**2 + 2*a - 5)/(2*a**2 - 1)
  17. Exercise 43, problem 24

    $\displaystyle 2 x^2 + x - 3 - \frac{x - 2}{3 x^2 + 1}$

    Printed answer:
    • $\displaystyle \frac{6x^4+3x^3-7x^2-1}{3x^2+1}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes (6*x**4 + 3*x**3 - 7*x**2 - 1)/(3*x**2 + 1)
  18. Exercise 43, problem 25

    $\displaystyle \frac{3x + 2}{x^2 + x + 2} - 1$.

    Printed answer:
    • $\displaystyle \frac{4x-x^2}{x^2-x+2}$.

    unverified: no computed check settled this one (yet)

    How it was checked
    • identity: the printed answer does not match the problem (4*x - x**2)/(x**2 - x + 2)
  19. Exercise 43, problem 26

    $\displaystyle 1 - \frac{2a^2 + 3}{a^2 - 2a + 3}$.

    Printed answer:
    • $\displaystyle -\frac{a^2+2a}{a^2-2a+3}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes -(a**2 + 2*a)/(a**2 - 2*a + 3)
  20. Exercise 43, problem 27

    $\displaystyle \frac{a^2}{a^2 - a + 3} - a^2 - a - 1$.

    Printed answer:
    • $\displaystyle -\frac{a^4+2a^2+2a+3}{a^2-a+3}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes -(a**4 + 2*a**2 + 2*a + 3)/(a**2 - a + 3)
  21. Exercise 43, problem 28

    $\displaystyle \frac{x^4}{x^2 + x - 1} - x^2 + x - 1$.

    Printed answer:
    • $\displaystyle \frac{x^2-2x+1}{x^2+x-1}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes (x**2 - 2*x + 1)/(x**2 + x - 1)
  22. Exercise 43, problem 29

    $\displaystyle \frac{a^2}{2}, \frac{xy}{3}, \frac{5ab^2}{4}.$

    Printed answer:
    • (none printed)

    unverified: no computed check settled this one (yet)

    How it was checked
    • other: not a kind the checker handles
  23. Exercise 43, problem 3

    $\displaystyle \frac{x^2 + y^2 + 3}{x - y}$

    Printed answer:
    • $\displaystyle x+y+\frac{3}{x-y}$.

    unverified: no computed check settled this one (yet)

    How it was checked
    • identity: the printed answer does not match the problem x + y + 3/(x - y)
  24. Exercise 43, problem 30

    $\displaystyle \frac{x^3}{3}, \frac{am}{2}, \frac{3x^2y}{5}.$

    Printed answer:
    • (none printed)

    unverified: no computed check settled this one (yet)

    How it was checked
    • other: not a kind the checker handles
  25. Exercise 43, problem 31

    $\displaystyle \frac{7x^2}{3y}, \frac{5xy}{2a}, \frac{x^3}{ay}.$

    Printed answer:
    • (none printed)

    unverified: no computed check settled this one (yet)

    How it was checked
    • other: not a kind the checker handles
  26. Exercise 43, problem 32

    $\displaystyle \frac{2a^2}{7m}, \frac{5ab}{3n}, \frac{b^4}{mn}.$

    Printed answer:
    • (none printed)

    unverified: no computed check settled this one (yet)

    How it was checked
    • other: not a kind the checker handles
  27. Exercise 43, problem 33

    $\displaystyle \frac{5}{y+x}, \frac{3x}{x-y}, \frac{2ab}{x^2-y^2}.$

    Printed answer:
    • (none printed)

    unverified: no computed check settled this one (yet)

    How it was checked
    • other: not a kind the checker handles
  28. Exercise 43, problem 34

    $\displaystyle \frac{2}{3+a}, \frac{5a}{a-3}, \frac{2ax}{a^2-9}.$

    Printed answer:
    • (none printed)

    unverified: no computed check settled this one (yet)

    How it was checked
    • other: not a kind the checker handles
  29. Exercise 43, problem 35

    $\displaystyle \frac{b^2}{a^2-ab}, \frac{a^2b}{a^2-b^2}.$

    Printed answer:
    • (none printed)

    unverified: no computed check settled this one (yet)

    How it was checked
    • other: not a kind the checker handles
  30. Exercise 43, problem 36

    $\displaystyle \frac{m^3}{nm+n^2}, \frac{m^2n}{m^2-n^2}.$

    Printed answer:
    • (none printed)

    unverified: no computed check settled this one (yet)

    How it was checked
    • other: the record may be misread
  31. Exercise 43, problem 37

    $\displaystyle \frac{2}{x^4-y^4}, \frac{3}{x^2 + xy - 2y^2}.$

    Printed answer:
    • (none printed)

    unverified: no computed check settled this one (yet)

    How it was checked
    • other: not a kind the checker handles
  32. Exercise 43, problem 38

    $\displaystyle \frac{5}{a^8-b^8}, \frac{2}{a^4 - 4a^2b^2 + 3b^4}.$

    Printed answer:
    • (none printed)

    unverified: no computed check settled this one (yet)

    How it was checked
    • other: not a kind the checker handles
  33. Exercise 43, problem 39

    $\displaystyle \frac{a-1}{a^2-2a-15}, \frac{a+2}{a^2+a-6}, \frac{a+3}{a^2-7a+10}.$

    Printed answer:
    • (none printed)

    unverified: no computed check settled this one (yet)

    How it was checked
    • other: not a kind the checker handles
  34. Exercise 43, problem 4

    $\displaystyle \frac{a^3 + b^3 + 3}{x - y}$

    Printed answer:
    • $\displaystyle a^2-ab+b^2-\frac{2}{a+b}$.

    unverified: no computed check settled this one (yet)

    How it was checked
    • identity: the printed answer does not match the problem a**2 - a*b + b**2 - 2/(a + b)
  35. Exercise 43, problem 40

    $\displaystyle \frac{x+1}{x^2-x-6}, \frac{x-2}{x^2+6x+8}, \frac{x+2}{x^2+x-12}.$

    Printed answer:
    • (none printed)

    unverified: no computed check settled this one (yet)

    How it was checked
    • other: not a kind the checker handles
  36. Exercise 43, problem 41

    $\displaystyle \frac{x^2+3x+2}{x^2-x-6}, \frac{x^2-x}{x^2+5x+4}, \frac{x^2-6x+9}{x^2+x-12}.$

    Printed answer:
    • (none printed)

    unverified: no computed check settled this one (yet)

    How it was checked
    • other: not a kind the checker handles
  37. Exercise 43, problem 42

    If $x$ quarts of milk cost $m$ cents, what will one pint cost?

    Printed answer:
    • $\displaystyle \frac{m}{2x}$ ct.

    verified: the printed answer passed a computed check

    How it was checked
    • solve: passes, with the problem read into an equation {p: m/(2*x)}
  38. Exercise 43, problem 43

    Express four consecutive numbers of which $a$ is the largest.

    Printed answer:
    • $a-3$, $a-2$, $a-1$, $a$.

    verified: the printed answer passed a computed check

    How it was checked
    • solve: passes, with the problem read into an equation {n1: a - 3, n2: a - 2, n3: a - 1, n4: a}
  39. Exercise 43, problem 44

    What is the next even number above $2m$?

    Printed answer:
    • $2m+2$.

    unverified: no computed check settled this one (yet)

    How it was checked
    • other: not a kind the checker handles 2*m + 2
  40. Exercise 43, problem 45

    What is the next odd number below $4a+1$?

    Printed answer:
    • $4a-1$.

    unverified: no computed check settled this one (yet)

    How it was checked
    • other: not a kind the checker handles 4*a - 1
  41. Exercise 43, problem 5

    $\displaystyle \frac{6 a^3 b^2 c - 9 a^2 b^2 + 3 c}{3 a^2 b}$

    Printed answer:
    • $\displaystyle 2abc-3b+\frac{c}{a^2b}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes 2*a*b*c - 3*b + c/(a**2*b)
  42. Exercise 43, problem 6

    $\displaystyle \frac{6 x^3 y^2 + 10 x^2 y^2 z - 2 m}{2 x y^2}$

    Printed answer:
    • $\displaystyle 3x^2+5xz-\frac{m}{xy^2}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes 3*x**2 + 5*x*z - m/(x*y**2)
  43. Exercise 43, problem 7

    $\displaystyle \frac{x^3 + 2 x^2 - 2 x + 1}{x^2 - x - 1}$

    Printed answer:
    • $\displaystyle x+3+\frac{2x+4}{x^2-x-1}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes x + 3 + (2*x + 4)/(x**2 - x - 1)
  44. Exercise 43, problem 8

    $\displaystyle \frac{2 a^3 + a^2 - 2a + 1}{a^2 + a - 2}$

    Printed answer:
    • $\displaystyle 2a-1+\frac{3a-1}{a^2+a-2}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes 2*a - 1 + (3*a - 1)/(a**2 + a - 2)
  45. Exercise 43, problem 9

    $\displaystyle \frac{x^3 + y^3}{x - y}$

    Printed answer:
    • $\displaystyle x^2+xy+y^2+\frac{2y^3}{x-y}$.

    verified: the printed answer passed a computed check

    How it was checked
    • identity: passes x**2 + x*y + y**2 + 2*y**3/(x - y)