abc2- 2abc = 2142
abc x 10 + 2 - abc + 2000 = 2142
abc x 10 + 2 - abc = 2142 + 2000
abc x 10 + 2 - abc = 4142
abc x 9 = 4142 - 2
abc x 9 = 4140
abc = 4140 : 9
abc = 460
Vậy abc = 460
2-c=2 => c=0
ab02-2ab0=2142
0-b=4 (nhớ 1) => b=6
a602-2a60=2142
5-a=1 => a=4
nên abc=460
\(abc2-2abc=2142\)
\(\Rightarrow abc\cdot10+2-2000-abc=2142\)
\(\Rightarrow abc\cdot10-abc=2142+2000-2\)
\(\Rightarrow abc\cdot9=4140\)
\(\Rightarrow abc=4140:9=460\)
VẬY \(abc=460\)
abc2 - 2abc = 2142
1000a + 100b + 10c + 2 - 2000 - 100a - 10b - c = 2142
900a + 90b + 9c - 1998 = 2142
9( 100a + 10b + c ) = 2142 + 1998
9( 100a + 10b + c ) = 4140
100a + 10b + c = 4140 : 9
100a + 10b + c = 460
<=> abc = 460
Vậy a = 4
b = 6
c = 0
