若x^2+4y^2+2x-4y+2=0,求根号5x^2+16y^2的值.

若x^2+4y^2+2x-4y+2=0,求根号5x^2+16y^2的值.
若x^2+4y^2+2x-4y+2=0,求根号5x^2+16y^2的值.

若x^2+4y^2+2x-4y+2=0,求根号5x^2+16y^2的值.
x^2+2x+4y^2-4y+2=0
(x^2+2x+1)+(4y^2-4y+1)=0
(x-1)^2+(2y-1)^2=0
x=1,y=0.5
5x^2+16y^2
=5+4
=9
所以根号5x^2+16y^2的值为3.