(x+y-1)的2次方与[x+2]互为相反数
(x+y-1)的2次方+[x+2]互为相反数=0
x+y=1
x+2=0
x=-2
y=3
a,b互为倒数
ab=1
x的y次方+ab
=(-2)^3+1
=-8+1
=-7