ab + bc + ca = abc
( a x 10 + b ) + ( b x 10 + c ) + ( c x 10 + a ) = a x 100 + b x 10 + c
a x 11 + b x 11 + c x 11 = a x 100 + b x 10 + c
b x 11 - b x 10 + c x 11 - c = a x 100 - a x 11
b + c x 10 = a x 89
=> a = 1 ; b = 9 ; c = 8
Vậy a = 1 ; b = 9 ; c = 8
TK mk nha !!