12abc0 = abc x 810
12 x 10000 + 10 x abc = abc x 810
120000 = abc x 810 - 10 x abc
abc x (810 - 10) = 120000
abc x 800 = 120000
abc = 120000 : 800 = 150
Vậy abc = 150
Ta có 12abc0 = abc x 810
=> 120 000 + abc x 10 = 810 x abc
=> 120 000 = 800 x abc
=> abc = 150
Vậy abc = 150