Answer:
its 4
Step-by-step explanation:
3(4)+3=15
12+3=15
15=15
Alexa has a great solution. Here's another way to see why the answer is x = 4
3x+3 = 15
3x+3-3 = 15-3 ... subtract 3 from both sides
3x = 12
3x/3 = 12/3 .... divide both sides by 3
x = 4
Effectively, you follow PEMDAS in reverse undoing the operations until you fully isolate x.
