Question

因式分解，9（a+b）²－4（a-b）²

Answer 1

9（a+b）²－4（a-b）²
= （3a+3b）²－（2a-2b）²
= (3a+3b+2a-2b)(3a+3b-2a+2b)
= (5a+b)(a+5b)

Answer 2

9(a^+2ab+b^)-4(a^-2ab+b^)
=5a^+26ab+5b^
=(a+5b)(5a+b)