Question

解方程组： x^2+y^2=5 2x^2-3xy-2y^2=0

Answer 1

2x^2-3xy-2y^2=0

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

所以x=-1/2y,或x=2y

将x=-1/2y代入x^2+y^2=5得,y1=2,y2=-2,所以x1=-1,x2=1

将x=2y 代入x^2+y^2=5得：y3=1,y4=-1,所以x3=2,x4=-2