xy/2=x+y+根号下(x²+y²)
xy/2-(x+y)=√x²+y²
[xy/2-(x+y)]²=x²+y²
x²y²/4-x²y-xy²+(x+y)²=x²+y²
x²y²-4x²y-4xy²+4x²+8xy+4y²=4x²+4y²
x²y²-4xy(x+y)+8xy=0
xy-4(x+y)+8=0
xy-4x-4y+8=0
(x-4)y=4x-8
y=(4x-8)/(x-4)
xy/2=x+y+根号下(x²+y²)
xy/2-(x+y)=√x²+y²
[xy/2-(x+y)]²=x²+y²
x²y²/4-x²y-xy²+(x+y)²=x²+y²
x²y²-4x²y-4xy²+4x²+8xy+4y²=4x²+4y²
x²y²-4xy(x+y)+8xy=0
xy-4(x+y)+8=0
xy-4x-4y+8=0
(x-4)y=4x-8
y=(4x-8)/(x-4)