求方程xy+4x+y-7=0的整数解
问题描述：
求方程xy+4x+y-7=0的整数解
答
y(x+1) + 4(x+1) = 11,(x+1)(y+4) = 11,有四组解.x + 1 = 1,x = 0,y + 4 = 11,y = 7.或者x + 1 = -1,x = -2,y + 4 = -11,y = -15.或者x + 1 = 11,x = 10,y + 4 = 1,y = -3.或者x + 1 = -11,x = -12,y + 4 = -1,y = -...