plug 3 in
5a - 10 (3) = 45
5a - 30 = 45
Perform the opposite operation by adding 30 on both sides of the equation
5a = 75
Perform the opposite operation of dividing both sides of the equation by 5
5's cross out on the left
5/5=1
Result will be 15 on the right
75/5 = 15
a = 15