用换元法解方程组 13/x+1 +7/y+1=9 6/x+1+7/2(y+1)=5
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![用换元法解方程组 13/x+1 +7/y+1=9 6/x+1+7/2(y+1)=5](/uploads/image/z/580405-13-5.jpg?t=%E7%94%A8%E6%8D%A2%E5%85%83%E6%B3%95%E8%A7%A3%E6%96%B9%E7%A8%8B%E7%BB%84+13%2Fx%2B1+%2B7%2Fy%2B1%3D9+6%2Fx%2B1%2B7%2F2%28y%2B1%29%3D5)
用换元法解方程组 13/x+1 +7/y+1=9 6/x+1+7/2(y+1)=5
用换元法解方程组 13/x+1 +7/y+1=9 6/x+1+7/2(y+1)=5
用换元法解方程组 13/x+1 +7/y+1=9 6/x+1+7/2(y+1)=5
令a=1/(x+1),b=1/(y+1)
所以13a+7b=9 (1)
6a+7b/2=5 (2)
(1)-(2)×2
a=-1
b=22/7
1/(x+1)=-1
x+1=-1
x=-2
1/(y+1)=22/7
y+1=7/22
y=-15/22
所以x=-2,y=-15/22
由第一个方程可知 x=13y/(7y-7)
代入第二个方程即可