Question

初中数学解方程！！求解！急！！在线等！

一共四题解方程组！
1. x-y=1,x2+xy+y2=1
2.x2+y2=6x,x+2y=0
3.x2-y2=3,x2-2xy+y2=1
4.4x2+4xy+y2=9,x2+5xy-6y2=0
求过程在线等！！

Answer 1

1.将x-y=1代入x^2+xy+y^2
=(1+y)^2+(1+y)y+y^2
=3y^2+3y
=0
得 y=0或y=-1
2. x+2y=0
x=-2y
代入x^2+y^2=6x
4y^2+y^2=-12y
5y^2+12y=0
得y=0或y=-12/5
3.x2-2xy+y2=1
得（x-y)^2=1
x=1+y或x=-1+y
当x=1+y时
代入x^2-y^2=3
得（1+y)^2-y^2=3
y=1,x=2
当x=-1+y时
代入x^2-y^2=3
得(y-1)^2-y^2=3
y=-1,x=-2
4.4x2+4xy+y2=9
得（2x+y)^2=9
y=3-2x或y=-3-2x
当y=3-2x时代入x2+5xy-6y2=0
11x^2-29x+18=0
得x=1或18/11
x=1时y=1
x=18/11时y=-3/11
当y=-3-2x时代入x2+5xy-6y2=0
11x^2+29x+18=0
x=-1或x=-18/11
当x=-1时y=-1
当x=-18/11时y=3/11