因为8/(x+y) +18/(x-y) = 4/3,两边乘以3得
24/(x+y) +54/(x-y) = 4
两边同时减去
24/(x+y) +24/(x-y) = 7/3
得
30/(x-y) = 5/3
所以x-y=18
代入
8/(x+y) +18/(x-y) = 4/3
得x+y = 24
所以x=21, y=3
谢谢采纳 ^_^