Hi Brittany,
To solve this or any other algebra problem, we need to find the value of the variable, in this case "x." Variables stand in for a number when you don't know that number yet.
To solve for a variable, we want to get it all by itself on one side of the equation. WE then try to get all the numbers we do know on the other side of the equation. To do this, we have to reverse operations every time we go over the equal sign: so if we're adding a number on one side, we take it away to get rid of it and then subtract it from the other side as well. If we're multiplying, we divide to get rid of it on one side and divide the other side by it as well. And vice versa. The important thing is always doing the same thing to both sides.
So:
1) 3x + 5 = 12
2) We're going to subtract 5 from each side, so 3x = 7
3) Now, we're going to divide each side by 3, so x = 7/3 (or, 2 and 1/3)
x = 2 and 1/3... it's that easy!
