Answer:
x=15
Explanation:
First, distribute into the parenthesis by 1 to get rid of the parenthesis.
The 1 is also called an "invisible one" to distribute into parenthesis.
3x+8x+15= 180
Now, add the common variables.
11x+15= 180
Subtract to both sides by 15.
11x+15= 180
-15 -15
Now divide both sides by 11 to isolate the variable.
11x= 165
11 11
x= 15