Question

几道题用分解因式公式法(完全平方公式)

Answer 1

(1)(x+2y)^2-6(x+2y)+9 =(x+2y-3)^2

(2)(x+y)^2-6(x+y)z+9z^2=(x+y-3z)^2

(3)(a+b)^2-4(a+b)+4(a-b)^2=(a+b-2(a-b))^2=(3b-a)^2