Okay, so first we will need to combine like terms.
The like terms in the question are -15s and 13.5s.
Combining usually means addition. So you add -15s and 13.5s.
That would be -1.5s.
Now we need to combine the rest of the equation, and that would be 12.81 + 15.71 + 17.2
The answer to that would be 45.72
Now combine the two answers
-1.5s = 45.72
The next step is to divide each term by -1.5
-1.5 ÷ -1.5s would just leave us with s.
Now,
-1.5 ÷ 45.72 will be -30.48.
So you're answer is s = -30.48
Hope this helped! :D
