1 .a三次方+ab²-2a²b 2.4-12(x-y)+9(x-y)²

问题描述:

1 .a三次方+ab²-2a²b 2.4-12(x-y)+9(x-y)²

a三次方+ab²-2a²b
=a(a^2+b^2-2ab)
=a(a^2-2ab+b^2)
=a(a-b)^2
4-12(x-y)+9(x-y)²
=2^2-2*2*3(x-y)+(3(x-y))^2
=(2-3(x-y))^2
=(2-3x+3y)^2
=(3y-3x+2)^2还有三题 1. (x²+y²)²-4x²y²2.(x²-6)²-6(x²-6)+9 3. (x-1)(x-3)+1(x²+y²)²-4x²y² =x^4+2x^2y^2+y^4-4x^2y^2=x^4-2x^2y^2+y^4=(x^2-y^2)^2=(x+y)^2(x-y)^2 (x²-6)²-6(x²-6)+9=(x^2-6)-2*(x^2-6)*3+3^2=((x^2-6)-3)^2=(x^2-6-3)^2=(x^2-9)^2=(x+3)^2(x-3)^2 (x-1)(x-3)+1=x^2-3x-x+3+1=x^2-4x+4=(x-2)^2