{x²-xy-3x=o{x²+y+1=0

{x²-xy-3x=o{x²+y+1=0
{x²-xy-3x=o
{x²+y+1=0

{x²-xy-3x=o{x²+y+1=0
{x²-xy-3x=o ①
{x²+y+1=0 ②
由①得x(x-y-3)=0
所以得
{x=0
{x²+y+1=0
或
{x-y-3=0
{x²+y+1=0
解
{x=0
{x²+y+1=0
得x=0,y=-1
解
{x-y-3=0
{x²+y+1=0
得x=-2,y=-5或x=1,y=-2
所以原方程组的解为x=0,y=-1或x=-2,y=-5或x=1,y=-2

一式:x(x-y)=3x
x-y=3 x=3+y
代入二式：y^2+7y+10=0
(y+5)(y+2)=0
y=-5或-2
x=-2或1
即一解x=-2,y=-5;
二解x=1,y=-2

x²-xy-3x=o
x（x-y-3）=0
x=0或x-y-3=0
将x=0代入x²+y+1=0，y=-1
将x-y-3=0与x²+y+1=0联立解得
两式相加x²+x-2=0
（x-1）（x+2）=0
x1=1 x2=-2
y1=-2 y2=-5
综上所述
x1=1，y1=-2
x2=-2，y2=-5
x3=0，y3=-1

{x²+y+1=0
y=-x^2-1代入x²-xy-3x=o得：
x^2-x*(-x^2-1)-3x=0
x^2+x^3+x-3x=0
x^3+x^2-2x=0
x(x^2+x-2)=0
x(x+2)(x-1)=0
x=0 x=-2 x=1
y=-x^2-1=-1或 -5或 -2
x=0,y=-1
x=-2,y=-5
x=1,y=-2

x-xy-3x=0①
x+y+1=0②
②得x=-y-1
代入①-y-1-(-y-1)y-3(-y-1) 得-y-1-(-y²-y)+3y+1=0
-y-1+3y+y²+y+1=0
y²+3y=0\7
连到一起了。。