题目内容：

已知x、y满足x^2+4y^2+2x-4y+2=0,则根号下5x^2+16y^2=

优质解答

x^2+4y^2+2x-4y+2=0
x^2+2x+1+4y^2-4y+1=0
(x+1)^2+(2y+1)^2=0
x=-1 y=-1/2
5x^2+16y^2=5*(-1)^2+16*(-1/2)^2=5+4=9