方程组:x(y+1)+2(y+1)=y(y-1)x-5(y-1) x(4+y)-y(8-x)=-20x(y+1)+2(y+1)=y(y-1)x-5(y-1) x(4+y)-y(8-x)=-20(这是一个方程组.)

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方程组:x(y+1)+2(y+1)=y(y-1)x-5(y-1) x(4+y)-y(8-x)=-20x(y+1)+2(y+1)=y(y-1)x-5(y-1) x(4+y)-y(8-x)=-20(这是一个方程组.)

方程组:x(y+1)+2(y+1)=y(y-1)x-5(y-1) x(4+y)-y(8-x)=-20x(y+1)+2(y+1)=y(y-1)x-5(y-1) x(4+y)-y(8-x)=-20(这是一个方程组.)
方程组:x(y+1)+2(y+1)=y(y-1)x-5(y-1) x(4+y)-y(8-x)=-20
x(y+1)+2(y+1)=y(y-1)x-5(y-1)
x(4+y)-y(8-x)=-20
(这是一个方程组.)

方程组:x(y+1)+2(y+1)=y(y-1)x-5(y-1) x(4+y)-y(8-x)=-20x(y+1)+2(y+1)=y(y-1)x-5(y-1) x(4+y)-y(8-x)=-20(这是一个方程组.)
1\先将X(Y+1)+2(Y+1)=Y(Y-1)X-5(Y-1)化简为
2\X=Y的平方-8Y+3除以Y+1
3\将X=Y的平方-8Y+3除以Y+1
代入X(4+Y)-Y(8-X)=-20
4\得式XXXXXX(百度这里打不出来,不过这一步很容易的想来你应该没问题)
5\求得Y=1
6\将Y=1代入以上任一方程
7\求得X=-2
8\解得该方程解为X=-2;Y=1

先解y(y-1)x-5(y-1) x(4+y)-y(8-x)=-20
解出y以后将y带入x(y+1)+2(y+1)=-20算出x

(X-Y+1)(X+Y-5)=(x-y-5+6)(x-5+y)=(x-5-y)(x-5+y)+6(x-5+y)=(x-5)^2-y^2+6x+6y-30=x^2-y^2-4x+6y-5

先将X(Y+1)+2(Y+1)=Y(Y-1)X-5(Y-1)化简为
X=(Y^2-8Y+3)/(Y+1)
将X=(Y^2-8Y+3)/(Y+1)
代入X(4+Y)-Y(8-X)=-20
求得Y=1
将Y=1代入方程
求得X=-2
解得该方程解为X=-2;Y=1