abc+bb=cba
100a+10b+c+10b+b=100c+10b+a
100a+10b+10b+b+c=100c+10b+a
100a+21b+c=100c+10b+a
99a+11b+1=99c+1+1
\(\Rightarrow99a+11b=99c+1\)
Đến đây là mình tịt rồi
Ta có : abc + bb = cba
a . 100 + b . 10 + c . 1 + b . 10 + b . 1 = c . 1 + b . 10 + a . 1
a . 100 + ( b . 10 + b . 10 + b . 1 ) + c . 1 = c . 100 + b . 10 + a
a . 100 + b . 21 + c . 1 = c . 100 + b . 10 + a . 1
( a . 100 ) - a . 1 + ( b . 21 - b . 10 ) = c . 100 - c . 1
\(\Rightarrow\)a . 99 + b . 11 = c . 99
a . 9 + b = c . 9
\(\Rightarrow\)a = 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9
c = 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9
b = 0