a,3 + 2x-1=24-[42-(22-1)]
3 + 2x-1=24-[42-(4-1)]
3 + 2x-1=24-(16-3)
3 + 2x-1=24-13
3 + 2x-1=11
3 + 2x=11+1
3 + 2x=12
2x=12-3
2x=9(đề sai)
b,(3x-24).75=2 .76
(3x-16).16807=2 .117649
(3x-16).16807=235298
3x-16=235298:16807
3x-16=14
3x=14+16
3x=30
x=30:3
x=10