(y+1)/(x+1)=1/2..................1
(y-1)/(x-1)=2/5....................2
由1式得
x+1=2(y+1)
x+1=2y+2
x-2y=1
x=2y+1.................3
由2式得
2(x-1)=5(y-1)
2x-2=5y-5
2x-5y=-3...............4
将3式代入4式得
2(2y+1)-5y=-3
4y+2-5y=-3
-y=-5
y=5
x=2y+1=2*5+1=11
经检验x=11,y=5是方程的解
(y+1)/(x+1)=1/2. x= 2y+1 ----(1)
(y-1)/(x-1)= 2/5 , 2x=5y-3 --- (2)
(1)代入(2),得:y=5 代入(1)得:x= 11
所以:x=11, y=5
由 (y+1)/(x+1)=1/2 得 x-2 y=1①
由 (y-1)/(x-1)=2/5 得 2x-5y=-3②
①式两边同时乘以2由减去②式 得y=5 所以x=11
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