Factoring Practice Problems

Here you will find a concise collection of factoring practice problems. Visit this page directly at hunkim.com/factor

Factor fully:

  1. 3x-9
    Solution
    3(x-3)
  2. 15x^4y-20x^3y^5
    Solution
    5x^3y(3x-4y^4)
  3. \frac{x^2}{2}-2x
    Solution
    \frac{x}{2}(x-4)
  4. x^2-25
    Solution
    (x+5)(x-5)
  5. x^2+1
    Solution
    Cannot be factored
  6. 4a^2-9x^4b^2
    Solution
    (2a+3x^2b)(2a-3x^2b)
  7. \frac{4}{49}a^4 b^2-\frac{1}{100}
    Solution
    \left ( \frac{2}{7} a^2b+\frac{1}{10} \right) \left( \frac{2}{7} a^2b-\frac{1}{10}\right)
  8. 2a^2-18
    Solution
    2(a+3)(a-3)
  9. x^2+x-12
    Solution
    (x-3)(x+4)
  10. 2x^2+12x+18
    Solution
    2(x+3)^2
  11. \frac{x^2}{2}+x-4
    Solution
    =\frac{1}{2}(x^2+2x-8)
    =\frac{1}{2}(x+4)(x-2)
  12. 2x^2+x-6
    Solution
    (2x-3)(x+2)
  13. 200x^2+500x-1200
    Solution
    =100(2x^2+5x-12)
    =100(2x-3)(x+4)
  14. 10x^2+29x-21
    Solution
    (5x-3)(2x+7)
  15. x^4-81
    Solution
    =(x^2+9)(x^2-9)
    =(x^2+9)(x+3)(x-3)
  16. (x+1)x^2-(x+1)9
    Solution
    =(x+1)(x^2-9)
    =(x+1)(x+3)(x-3)
  17. 2(3x+2)^2+9(3x+2)-5
    Solution
    Let a=(3x+2)
    Factor 2a^2+9a-5
    =[2a-1][a+5]
    =[2(3x+2)-1][(3x+2)+5]
    =[6x+4-1][(3x+2)+5]
    =[6x+3][3x+7]
    =3[3x+1][3x+7]
  18. a^2(2x-3)+b^6(3-2x)
    Solution
    =a^2(2x-3)-b^6(2x-3)
    =(2x-3)(a^2-b^6)
    =(2x-3)(a+b^3)(a-b^3)
  19. Factor by grouping: x^3+7x^2+2x+14
    Solution
    =x^2(x+7)+2(x+7)
    =(x+7)(x^2+2)
  20. Challenge:
    1. What is the area of the shaded region below in fully factored form?

      Solution
      4\pi(x+1)
    2. Factor 2(\sin \theta)^2-5 \sin \theta -3
      Solution
      (2 \sin \theta+1)(\sin \theta -3)
    3. Factor e^{2x}-25 (e\approx 2.718 is a special constant)
      Solution
      (e^x+5)(e^x-5)
    4. x^2+kx+8. Find the possible values of k such that this trinomial can be factored
      Solution
      k=\pm 9, \pm 6
    5. Expand then factor:
      1. (x+y)(x^2-xy+y^2)
        Solution
        x^3+y^3
      2. (x-y)(x^2+xy+y^2)
        Solution
        x^3-y^3
    6. Factor 8a^6+b^3
      Solution
      (2x^2+b)(4a^4-2a^2b+b^2)
    7. Factor x^3-3x^2+4
      Solution
      (x-2)^2(x+1)
    8. Factor 2x^4+8x^3-4x^2-24x+18
      Solution
      2(x+3)^2(x-1)^2