x2+y2=1和x2+y2-4x+2y=4解这组方程,

x2+y2=1和x2+y2-4x+2y=4解这组方程,
x2+y2=1和x2+y2-4x+2y=4解这组方程,

x2+y2=1和x2+y2-4x+2y=4解这组方程,
两方程相减得：4x-2y=-3,即：y=2x+3/2
代入第1式得：x^2+4x^2+6x+9/4=1
5x^2+6x+5/4=0
x1=(-6+√11)/10,y1=2x1+3/2=(3+2√11)/10
x2=(-6-√11)/10,y2=2x2+3/2=(3-2√11)/10