Question

Which of the following statements describes a correct method for solving the equation below?

Answer 1

Selection A works best.

_____
The other choices get you to a place where further work is necessary. They don't really contribute to solving the equation.

Answer 2

A) is the correct answer. 

3x + 3 = 6x
3x-3x + 3 = 6x - 3x
(3x -3x cancel each other out, leaving you with 3)
3 = 3x
3/3 = 3x/3
1 = x
x = 1

Now Verify- 
3x + 3 = 6x
3(1) + 3 = 6(1)
3 +3 = 6
6 = 6

Now can also use the guess and check way. But this is my way of solving it. I hope it helped.