化简下列分式（要过程）：1 x²+x÷x²-1 2.x²-9÷x²-6x+9 3.x²+4x÷x²+8x+16 4.ab²（a-b）÷a²b-ab² 5.x²-8x+16÷x²-16 6.x²-2x÷2y-xy

1.(x²+x)/(x²-1) =x(x+1)/(x+1)(x-1) =x/x-12.(x²-9)/(x²-6x+9) =(x+3)(x-3)/(x-3)² =(x+3)/(x-3)3.(x²+4x)/(x²+8x+16) =x(x+4)/(x+4)² =x/(x+4)4.ab²(a-b)/(a...