16x9 - 16x Factor out 16x 16x(x8 - 16) The parentheses contains the difference of 2 perfect squares: 16x(x4 - 4)(x4 + 4) The parentheses contains the difference of 2 perfect squares: 16x(x2 - 2)(x2 + 2)(x4 + 4) The 3rd parentheses can become the difference of perfect squares if we play the trick of adding and subtracting 4x2 16x(x2 - 2)(x2 + 2)(x4 + 4 + 4x2 - 4x2) Swap the 2nd and 3rd terms in the 3rd parentheses 16x(x2 - 2)(x2 + 2)(x4 + 4x2 + 4 - 4x2) Change the third parentheses to brackets and enclose its first three terms in parentheses 16x(x2 - 2)(x2 + 2)[(x4 + 4x2 + 4) - 4x2] Factor the trinomial as a perfect square 16x(x2 - 2)(x2 + 2)[(x2 + 2)2 - 4x2] Now the bracket contains the difference of 2 perfect squares: 16x(x2 - 2)(x2 + 2)[(x2 + 2) - 2x][(x2 + 2) + 2x] Remove the parentheses inside the brackets: 16x(x2 - 2)(x2 + 2)[x2 + 2 - 2x][x2 + 2 + 2x] Arrange the trinmials in brackets in descending order and change the brackets to parentheses: 16x(x2 - 2)(x2 + 2)(x2 - 2x + 2)(x2 + 2x + 2) Here are 105 factors of that, pick any 5. 1. 1 2. 2 3. 4 4. 8 5. 16 6. x 7. (x2-2) 8. (x2+2) 9. (x2-2x+2) 10. (x2+2x+2) 11. x(x2-2) 12. x(x2+2) 13. (x2-2)(x2+2) 14. 2x(x2-2) 15. x(x2+2) 16. (x2-2)(x2+2) 17. 4x(x2-2) 18. x(x2+2) 19. (x2-2)(x2+2) 20. 8x(x2-2) 21. x(x2+2) 22. (x2-2)(x2+2) 23. 16x(x2-2) 24. x(x2+2) 25. (x2-2)(x2+2) 26. x(x2-2)(x2+2) 27. x(x2-2)(x2-2x+2) 28. x(x2-2)(x2+2x+2) 29. x(x2+2)(x2-2x+2) 30. x(x2+2)(x2+2x+2) 31. x(x2-2x+2)(x2+2x+2) 32. (x2-2)(x2+2)(x2-2x+2) 33. (x2-2)(x2+2)(x2+2x+2) 34. (x2-2)(x2-2x+2)(x2+2x+2) 35. (x2+2)(x2-2x+2)(x2+2x+2) 36. 2x(x2-2)(x2+2) 37. x(x2-2)(x2-2x+2) 38. x(x2-2)(x2+2x+2) 39. x(x2+2)(x2-2x+2) 40. x(x2+2)(x2+2x+2) 41. x(x2-2x+2)(x2+2x+2) 42. (x2-2)(x2+2)(x2-2x+2) 43. (x2-2)(x2+2)(x2+2x+2) 44. (x2-2)(x2-2x+2)(x2+2x+2) 45. (x2+2)(x2-2x+2)(x2+2x+2) 46. 4x(x2-2)(x2+2) 47. x(x2-2)(x2-2x+2) 48. x(x2-2)(x2+2x+2) 49. x(x2+2)(x2-2x+2) 50. x(x2+2)(x2+2x+2) 51. x(x2-2x+2)(x2+2x+2) 52. (x2-2)(x2+2)(x2-2x+2) 53. (x2-2)(x2+2)(x2+2x+2) 54. (x2-2)(x2-2x+2)(x2+2x+2) 55. (x2+2)(x2-2x+2)(x2+2x+2) 56. 8x(x2-2)(x2+2) 57. x(x2-2)(x2-2x+2) 58. x(x2-2)(x2+2x+2) 59. x(x2+2)(x2-2x+2) 60. x(x2+2)(x2+2x+2) 61. x(x2-2x+2)(x2+2x+2) 62. (x2-2)(x2+2)(x2-2x+2) 63. (x2-2)(x2+2)(x2+2x+2) 64. (x2-2)(x2-2x+2)(x2+2x+2) 65. (x2+2)(x2-2x+2)(x2+2x+2) 66. 16x(x2-2)(x2+2) 67. x(x2-2)(x2-2x+2) 68. x(x2-2)(x2+2x+2) 69. x(x2+2)(x2-2x+2) 70. x(x2+2)(x2+2x+2) 71. x(x2-2x+2)(x2+2x+2) 72. (x2-2)(x2+2)(x2-2x+2) 73. (x2-2)(x2+2)(x2+2x+2) 74. (x2-2)(x2-2x+2)(x2+2x+2) 75. (x2+2)(x2-2x+2)(x2+2x+2) 76. x(x2-2)(x2+2)(x2-2x+2) 77. x(x2-2)(x2+2)(x2+2x+2) 78. x(x2-2)(x2-2x+2)(x2+2x+2) 79. x(x2+2)(x2-2x+2)(x2+2x+2) 80. (x2-2)(x2+2)(x2-2x+2)(x2+2x+2) 81. 2x(x2-2)(x2+2)(x2-2x+2) 82. x(x2-2)(x2+2)(x2+2x+2) 83. x(x2-2)(x2-2x+2)(x2+2x+2) 84. x(x2+2)(x2-2x+2)(x2+2x+2) 85. (x2-2)(x2+2)(x2-2x+2)(x2+2x+2) 86. 4x(x2-2)(x2+2)(x2-2x+2) 87. x(x2-2)(x2+2)(x2+2x+2) 88. x(x2-2)(x2-2x+2)(x2+2x+2) 89. x(x2+2)(x2-2x+2)(x2+2x+2) 90. (x2-2)(x2+2)(x2-2x+2)(x2+2x+2) 91. 8x(x2-2)(x2+2)(x2-2x+2) 92. x(x2-2)(x2+2)(x2+2x+2) 93. x(x2-2)(x2-2x+2)(x2+2x+2) 94. x(x2+2)(x2-2x+2)(x2+2x+2) 95. (x2-2)(x2+2)(x2-2x+2)(x2+2x+2) 96. 16x(x2-2)(x2+2)(x2-2x+2) 97. x(x2-2)(x2+2)(x2+2x+2) 98. x(x2-2)(x2-2x+2)(x2+2x+2) 99. x(x2+2)(x2-2x+2)(x2+2x+2) 100. (x2-2)(x2+2)(x2-2x+2)(x2+2x+2) 101. x(x2-2)(x2+2)(x2-2x+2) 102. 2x(x2-2)(x2+2)(x2-2x+2) 103. 4x(x2-2)(x2+2)(x2-2x+2) 104. 8x(x2-2)(x2+2)(x2-2x+2) 105. 16x(x2-2)(x2+2)(x2-2x+2) Edwin