设 十位数是 x ,则个位数是 x - 3
10x + x - 3 = 7(x + x - 3) - 6
11x - 3 = 14x - 21 - 6
14x - 11x = 21 + 6 - 3
3x = 24
x = 24÷3
x = 8
十位 = x = 8
个位 = x - 3 = 5
所以这个两位数是 85