Change the subject of a formula

Follow this one with me, a step at a time. Try to guess each step first.

Worked example 1

Make x the subject of the formula y = (6x + 2)/3.

Remember: Treat it like an equation in x, and undo what has been done to x, last operation first.

First multiply both sides by 3, which removes the denominator.
Next subtract 2 from both sides, and then divide both sides by 6.
The result is x = (3y − 2)/6.

Common mistakes

Divided only one term. Every term on that side has to be divided.
Moved a term across the equals sign without changing its sign.
Undid the operations in the wrong order. Work backwards from the last thing done to the subject.