(X+2的平方)减10(x+2)加25等于0

问题描述:

(X+2的平方)减10(x+2)加25等于0

(x+2)^2-10(x+2)+25=0
x^2+4x+4-10x-20+25=0
x^2-6x+9=0
(x-3)^3=0
x=3