若y=根号[(x^2-2)/(5x-4)]+[根号(x^2-2)/(4-5x)]+2
[(x^2-2)/(5x-4)]>=0
(x^2-2)/(4-5x)]>=0
两个相反数同时大于或等于0,两个必须都为0.
x^2-2=0
x^2=2
y=0+0+2=2
x^2+y^2=2+2^2=6