a) `16x + 40 = 10 . 3^2 + 5.(1+2+3)`
`16x + 40 = 10. 9 + 5. 6`
`16x + 40 = 90 + 30`
`16x + 40 = 120`
`16x = 120 -40`
`16x= 80`
`x= 80:16`
`x=5`
Vậy `x=5`
b) `92 - 2x = 2.4^2 - 3.4 +120:15`
`92 - 2x = 2.16 - 12 + 8`
`92 - 2x = 32 - 12 +8`
`92 - 2x= 20 +8`
`92 - 2x= 28`
`2x= 92 -28`
`2x = 64`
`x= 64 :2`
`x= 32`
Vậy `x =32`