Factor:
(2m - 3)² - (8m² - 4)²
Notice: This question on my homework has a bonus mark. I'm not sure why, and what's so special about it. Can someone help me find some extra "bonus" step at the end?
Thanks!
This is a DOTS (Difference of Two Squares) factorization.
(2m - 3)² - (8m² - 4)²
[(2m - 3) - (8m2 - 4)][(2m - 3) + (8m2 - 4)] ------ Applying DOTS, or
(2m - 3 - 8m2 + 4)(2m - 3 + 8m2 - 4)
(- 8m2 + 2m + 1)(8m2 + 2m - 7)
(- 8m2 + 4m - 2m + 1)(8m2 + 2m - 7) ----- Factoring - 8m2 + 2m + 1
(- 8m2 + 4m - 2m + 1)(8m2 + 2m - 7)
[- 4m(2m - 1) - 1(2m - 1)](8m2 + 2m - 7)
(- 4m - 1)(2m - 1)(8m2 + 2m - 7) or - (4m + 1)(2m - 1)(8m2 + 2m - 7)