The question is 3 + 6(x) = 15
so you need to find x
so you should add -3 on both sides of the equation and you will have:
6(x) = 15 -3
6(x) = 12
now you can divide both sides by 6 and you will have:
x = 12/6
x = 2 :)))
I hope this is helpful
have a nice day