(x + 4)(y - 1) = xy
xy - x + 4y - 4 = xy
-x + 4y = 4 ....................(1)
(x - 2)(y + 1) = xy
xy + x - 2y - 2 = xy
x - 2y = 2 ......................(2)
(1) + (2)得
2y = 6
y = 3 .....代入(2)得
x = 8
(x+4)(y-1)=xy+4y-x-4=xy ①
(x-2)(y+1)=xy+x-2y-2=xy ②
把①②移项得
4y-x-4=0③
x-2y-2=0④
解③④得
x=8
y=3
两边分别展开就会发现xy项都消掉了,变成了2个一次方程
然后就能解啦~