Tìm x

a)105 - 5 . ( x + 8 ) = 25

b)128 - 3 . (x + 4 ) = 23

`a)  105 - 5.(x+8) = 25`

`5. (x+8) = 105-25`

`5. (x+8) = 80`

`x + 8 = 16`

`x = 16 - 8`

`x = 8`

Vậy `x=8`

`b)  128 - 3. (x+4) = 23`

`3 . (x+4) = 128 - 23`

`3 . (x+4) = 105`

`x+4 = 105 : 3`

`x + 4 = 35`

`x = 35 - 4`

`x = 31`

Vậy `x=31`

`#` $khoinguyentien$