Question

因式分解,1) 0.01n^3-4/9m^2 2)25(a+b)^2-9(a-b)^2 3)-x^2-4y^2+4xy4

Answer 1

2）25(a+b)^2-9(a-b)^2

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

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

=[5a+5b+3a-3b][5a+5b-3a+3b]

=[8a+2b][2a+8b]

=2(4a+b)*2(a+4b)

=4(4a+b)(a+4b)

（3）-x^2-4y^2+4xy

=-(x^2+4y^2-4xy)

=-(x-2y)^2

4）(a-b)^2+2(a-b)+1

=（a-b）(2+a-b)+1

=