\begin{array}{c|c|c}\color{gainsboro}{𝕻𝖍}\color{lightgrey}{𝖚𝖔}\color{silver}{𝖓𝖌}\color{darkgray}{𝕿𝖍}\color{gray}{𝖆}\color{dimgray}{𝖓}\color{black}{𝖍}\end{array}

`b)` `1/3+2/3:x=-7`

`2/3:x=-7-1/3`

`2/3:x=(-22)/3`

`x=2/3:((-22)/3)`

`x=(-1)/11`

Vậy `x=(-1)/11.`

`c)` `2/3:x=1,4-12/5`

`2/3:x=7/5-12/5`

`2/3:x=-1`

`x=2/3:(-1)`

`x=(-2)/3`

Vậy `x=(-2)/3.`