Question

Solve 3x+1=3. What is x plz?

Answer 1

3x+1=3
3x=3-1
3x=2
x=2/3

Answer 2

We can solve simple algebras by reversing the mathematical symbols and shifting the number or unknown to the other side of the equation. 
+ turns to -
x turns to ÷
(or vice versa)

So, first step to solve this, 
shift +1 to the other side, turn it into -1.
3x = 3 - 1
3x = 2
Now, shift x3 to the other side, turn it into ÷3.
x = 2 ÷ 3
x = 2/3 (or 0.6666666...)