Question

因式分解 4(a+b)的平方-9（a-b）的平方，25x的平方-1分之16y的平方

Answer 1

4(a+b)的平方-9（a-b）的平方

=[2(a+b)]²-[3(a-b)]²
=[2(a+b)+3(a-b)][2(a+b)-3(a-b)]
=(5a-b)(5b-a)

25x²-1/(16y²)
=(5x)²-[1/(4y)]²
=(5x+1/4y)(5x-1/4y)

Answer 2

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

(25x^2-1)/16
=1/16*(25x^2-1)
=1/16*(5x+1)(5x-1)