Mathematics for IGCSE & O level - Equations (Section 3 - No. 1)

In the context of completing the square, what is the purpose of adding a number to the left-hand side of the equation?

To factorize the left-hand side.

To make the left-hand side a complete square.

To isolate the constant term.

To simplify the equation.

Adding a number to the left-hand side allows to make the left-hand side a complete square.