已知x-y+1的绝对值与x²+8x+16互为相反数,则x²+2xy+y²=_____
问题描述:
已知x-y+1的绝对值与x²+8x+16互为相反数,则x²+2xy+y²=_____
答
x-y+1的绝对值大于等于0,x²+8x+16=(x+4)² 也是大于等于0两个大于等于0的数互为相反数,那这两个数都是0x-y+1=0x²+8x+16=(x+4)² =0解得x=-4,那y=-3x²+2xy+y²=(x+y)²=...