Question

-x-y/(x-y)^2=

化简

Answer 1

原式=(-x³+2x²y-xy²-y)/(x²-2xy+y²)

Answer 2

x=-1，y=1
x=2，y=-2
所以
1=-k+b
-2=2k+b
相减
3k=-3
k=-1
b=1+k=0
x=1
1+b+c=8 (1)
x=-4
16-4b+c=8 (2)
(1)-(2)
-15+5b=0
b=3
c=8-1-b=4