计算:(1)x²-9/(x²+6x+9)·1/(2x-6) (2)x²-y²/(x+2y)÷x+y/(x²+2xy)

问题描述:

计算:(1)x²-9/(x²+6x+9)·1/(2x-6) (2)x²-y²/(x+2y)÷x+y/(x²+2xy)
(3)x²-2x+1/(x²+4x+4)÷(x-1)·x²+3x+2/(x-1)