设原来的数为10x+y
x+y = 8 (1)
10y+x = 10x+y +54 (2)
9x-9y+54=0
9x-9(8-x) +54 =0
18x = 18
x =1
from (1)
y = 7
设原来的数为 = 17
解设十位数字是(x)则个位数字是8-x
10(8-x)+x=10x+(8-x)+x +54
x=1
8-x=7
原来的数是:17
解设个位数字是x则十位数字是(8-x)
54-10(8-x)=10(8-x)+x