Question

已知 Ix-y+1I 与x²+8x+16互为相反数,求x²+2xy+y²

Answer 1

Ix-y+1I +x²+8x+16=0

Ix-y+1I +(x+4)^2=0

x=-4

x-y+1=0

y=-3

x²+2xy+y²

=(x+y)^2

=49