解下列方程组:

问题描述:

解下列方程组:
{x(2x-3)=0,y=x²-1
{(3x+4y-3)(3x+4y+3)=0,3x+2y=5
{(x-y+2)(x+y)=0,x²+y²=8
{(x+y)((x+y-1)=0,(x-y)(x-y-1)=0

x(2x-3)=0 ===> x=0,或者x=3/2
所以,y=x^2-1=-1,或者y=5/4
(3x+4y-3)(3x+4y+3)=0
===> 3x+4y-3=0,或者3x+4y+3=0
===> 3x+3y=3,或者3x+4y=-3
又,3x+2y=5
所以,x=3,y=-2;或者x=13/3,y=-4
(x-y+2)(x+y)=0
===> x-y+2=0,或者x+y=0
===> x-y=-2,或者x=-y
又x^2+y^2=8
①x-y=-2,x^2+y^2=8
===> (y-2)^2+y^2=8
===> y^2-4y+4+y^2=8
===> 2y^2-4y-4=0
===> y^2-2y-2=0
===> (y-1)^2=3
===> y=1±√3
所以,x=y-2=-1±√3
即,x=-1+√3,y=1+√3;x=-1-√3,y=1-√3
②x=-y,x^2+y^2=8
===> 2x^2=8
===> x=±2
所以,y=±2
即,x=2,y=-2;x=-2,y=2
(x+y)(x+y-1)=0
===> x+y=0,或者x+y=1
(x-y)(x-y-1)=0
===> x-y=0,或者x-y=1
①x+y=0,x-y=0
所以,x=y=0
②x+y=0,x-y=1
所以,x=1/2,y=-1/2
③x+y=1,x-y=0
所以,x=y=1/2
④x+y=1,x-y=1
所以,x=1,y=0