a) 10.abc+abc=4048
11.abc=4048 =>abc=4048:11=368
=> abc=368
b) 10.abc+2-2000-abc=2142
9.abc=4140 =.abc=4140:9=460
=> abc=460
a)abc+ab,c=404,8 b)abc2-2abc=2142
abc2=2142+2abc
abc*10+abc=4048 abc*10+2=2142+2000+abc
abc*11=4048 cùng bớt cả 2 vế đi abc
abc=4048/11 abc*9+2=4142
abc*9=4142-2=4140
abc=4140/9=460
abc=368