约分 x²-9分之x²+6x+9

问题描述:

约分 x²-9分之x²+6x+9

=(x+3)(x-3)分之(x+3)的平方=x-3分之x+3

(x+3)(x+3)/(x+3)(x-3)=x+3/x-3

x²-9=(x+3)(x-3)
x²+6x+9=(x+3)²
x²+6x+9/x²-9
=(x+3)²/(x+3)(x-3)
=(x+3)/(x-3)

(x+3)²/(x-3)(x+3)=(x+3)/(x-3)