Mathematics for IGCSE & O level - Equations (Section 7 - No. 39)

Which of these are key steps when applying the quadratic formula?

Identify the values of a, b, and c from the quadratic equation.

Substitute these values into the formula.

Simplify the equation and solve for x.

Always change the subject of a formula before solving.

All but the subject change are key steps in using the quadratic formula.