What you do is distribute the 4.5 into what is inside the parenthesis. This gives you 7+4.5+18x = -17.5. You pass over the 7+4.5 to the other side, which gives you ...
11.5 + 18x = -17.5
-11.5. -11.5
18x = - 29
Then you divide both sides by 18 to isolate the variable
