y+1=2(x -1 ) ,y-2x=-3 ①
y-1=x+1 y-x=2 ②
②-①得:
-x+2x=2-(-3)
x=5
y=7
y+1=2(x -1 ) 化简为 2x-y=3 1 y-1=x+1 化简为 x-y=-2 2 然后1-2得x=5 带入得y=7
y+1=2(x -1 ) 代入: y-1=x+1
y+1=2x-2 2x-3=x+1
y=2x-3 x=5
x=5代入
y=2x-3
y=7 所以{x=5,y=7}
1式化简y=2(x-1)-1=2x-3代入2式2x-3-1=x+1得x=5 y=7
y+1=2(x-1) y=2x-3
y-1=x+1 y=x+2
2x-3=x+2
x=5
y=x+2
y=5+2
y=7
y-1=x+1移项得y=x+2
再将y=x+2 带入y+1=2(x-1)得x+2+1=2x-2
得x=5 y=7