若x^2+4y^2+2x减4y+2=0,求根号5x^2+16y^2的值

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

若x^2+4y^2+2x减4y+2=0,求根号5x^2+16y^2的值
将x^2+4y^2+2x-4y+2=0配方得：（x+1）^2+4(y-1/2)^2=0所以x=-1,y=1/2.
故5x^2+16y^2=9.