Answer :
(12 + x)/3 = 5
Multiply each side by 3 :
12 + x = 15
Subtract 12 from each side:
x = 3
=================================
x/3 - 5 = 3
Multiply each side by 3 :
x - 15 = 9
Add 15 to each side:
x = 24
Multiply each side by 3 :
12 + x = 15
Subtract 12 from each side:
x = 3
=================================
x/3 - 5 = 3
Multiply each side by 3 :
x - 15 = 9
Add 15 to each side:
x = 24