ban nao lam giup mik voi

Bài `5`:
`a, 91 - 5 .( 5 + x ) = 61`
`5 . (5 + x ) = 91 - 61`
`5 . (5 + x) = 30`
`5 + x = 30 : 5`
`5 + x = 6`
`x = 6 - 5`
`x=1`
Vậy `x = 1`

`b, [( x + 34 ) - 50] . 2 = 56`
`(x+ 34 ) - 50 = 56 : 2`
`(x+34)- 50 = 28`
`x + 34 = 28 + 50`
`x + 34 = 78`
`x = 78 - 34`
`x = 44`
Vay `x = 44`

`c, 1045 - [215 - (3x-24)] = 5`
`215 - (3x-24) = 1045 - 5`
`215 - ( 3x - 24) = 1040`
`3x - 24  = 215 - 1040`
`3x - 24 = -825`
`3x = -825 + 24`
`3x = -801`
`x = -801 : 3`
`x = -267`
Vậy `x = -267`

`d, [195-(15x-27)].39 = 4212`
`195-(15x-27) = 4212 : 39`
`195-(15x-27) = 108`
`15x - 27 = 195 - 108`
`15x - 27 = 87`
`15x = 87 + 27`
`15x = 114`
`x = 114 : 15`
`x = 7,6`
Vậy `x = 7,6`

`e,30 - 3(x - 2) = 18`
`3(x-2) = 30 -18`
`3(x-2) = 12`
`x-2 = 12 : 3`
`x-2 = 4`
`x = 4 + 2`
`x = 6`
Vậy `x = 6`