Question

已知2x^2+4xy+5y^2-4x+2y+5=0,求y^x的值.

Answer 1

2x^2+4xy+5y^2-4x+2y+5

=(x²+4xy+4y²)+(x²-4x+4)+(y²+2y+1)

=(x-2y)²+(x-2)²+(y+1)²=0

x-2=0

y+1=0

x+2y=0

x=2,y=-1

y^x=(-1)²=1