A quadratic equation looks like this:

ax² + bx + c = 0  (where 'a' cannot be zero.)

Solving the equation means finding ‘x’ values that make the equation true. These ‘x’ values are called the roots  of the quadratic.

Quadratic equations can have 0, 1 or two roots.

The quadratic formula is derived from the general quadratic equation (below) by completing the square.

The general quadratic equation:

ax² + bx + c = 0

has roots:

This quadratic formula is also called the ABC formula because it involves 3 parameters a, b, and c.