2-x/x²-9(1+2x-7/x²-4x+4)÷1/x+3
问题描述：
2-x/x²-9(1+2x-7/x²-4x+4)÷1/x+3
答
(2-x)/(x²-9)[1+(2x-7)/(x²-4x+4)]÷1/(x+3)
=(2-x)/[(x+3)(x-3)](x²-2x-3)/(x-2)²×(x+3)
=1/(x-3)×(x²-2x-3)/(x-2)
=1/(x-3)×(x-3)(x+1)/(x-2)
=(x+1)/(x-2)