Question 13592
2[s+3(s-1]=18
We first work inside the brackets, and distributethe 3.

2[s+3s-3]=18
Now we distribute the 2;
2s+6s-6=18
We +6 too both sides and add thhe 2s+6s;

8s-6+6=18+6
8s=24
Divide both sides by 8;
{{{8s/8=24/8}}}
s=3
Hope you understand
=)