3.5 Transposing Formulae with only + and – Signs

In a simple formula such as a = b – c we say that a is the subject of the formula, because it is isolated (on its own) on one side of the equation, with everything else on the other side.

To change the subject of the formula, or transpose the formula, we rearrange the equation so that a different letter is on its own.

Suppose we want to change the subject of the formula above to b. This means we want b on its own.