Answer:
15
Explanation:
since you are trying to find the value of X you need to take 20 and subtract it by 15 20 - 15 = 5 which means 20 - 5 = 15
we now know x = 5
we now have to multiply 3*x
since we know x = 5 we multiply 3*5 and get 15
3*5= 15
hope this helps!