`5[3a-2a(3a+6b)+6a^2]`

`= 5[3a-6a^2-12ab+6a^2]`

`= 5(3a-12ab)`

`= 15a-60ab`

*So the answer is;*

`5[3a-2a(3a+6b)+6a^2] = 15a-60ab`

`5[3a-2a(3a+6b)+6a^2]`

`= 5[3a-6a^2-12ab+6a^2]`

`= 5(3a-12ab)`

`= 15a-60ab`

*So the answer is;*

`5[3a-2a(3a+6b)+6a^2] = 15a-60ab`