\begin{array}{c|c|c}\color{gainsboro}{𝕹}\color{lightgrey}{𝖔}\color{silver}{𝖈}\color{darkgray}{𝖙}\color{gray}{𝖎}\color{dimgray}{𝖘}\color{black}{³⁴⁷}\end{array}

`(-3)^x*(-27)=3^8`

`(-3)^x*(-3)^3=(-3)^8`

`x+3=8`

`x=5`

`text{Vậy` `x=5.`

`-----------`

`8^3:x=16`

`x=8^3:16`

`x=512:16`

`x=32`

`text{Vậy` `x=32.`

`-----------`

`30-5x=-40`

`5x=30-(-40)`

`5x=70`

`x=70:5`

`x=14`

`text{Vậy` `x=14.`