Question

中华一题x的平方加y的平方减去8x减去4y加20等于0,求x,y

Answer 1

x^2+y^2-8x-4y+20=0

x^2-8x+16+y^2-4y+4=0

(x-4)^2+(y-2)^2=0

即(x-4)^2=0,x=4

(y-2)^2=0,y=2