Question

初一数学因式分解,求详细过程1.-a+2a²-a³2.9(x+2y)²-25(x-2y)&

Answer 1

-a+2a²-a³=a(-1+2a-a^2)=-a(a-1)²

9(x+2y)²-25(x-2y)²=[3(x+2y)+5(x-2y)][3(x+2y)-5(x-2y)]=(8x-4y)(16y-2x)

x²+x+1/4=(x+1/2)²

(7a-8b)²-4x²=(7a-8b-2x)(7a-8b+2x)

9(a-b)²+12(a-b)+4=[3(a-b)+2]²=(3a-3b+2)²