ai đó cứu tui zớiiiiiii

`a)`

`3,15 + x = 8,36`

`x = 8,36 - 3,15`

`x = 5,21`

`Vậy: x = 5,21`

`b)`

`x - 4/5 = (-1)/15`

`x = (-1)/15 + 4/5`

`x = 11/15`

`Vậy: x = 11/15`

`c)`

`5/2 : x = (-2)/3 : 5/3`

`5/2 : x = (-2)/5`

`x = 5/2 : (-2)/5`

`x = (-25)/4`

`Vậy: x = (-25)/4`

`d)`

`2/9 - 2x = 1/3`

`2x = 2/9 - 1/3`

`2x = (-1)/9`

`x = (-1)/9 : 2`

`x = (-1)/18`

`Vậy: x = (-1)/18`