## The Quadratic Formula

A quadratic equation is an equation of the formwhere We can solve equations of this form by identifying a, b and c and substituting them into the formula

to find

Example:

Solve

Then or

It is very important to get the correct values ofFor the following equations the values are given

Notice that if a minus sign appears in the formula we have to solve then that value ofwill be negative.

Then for the first equation

We may also solve quadratic equations by sketching a quadratic graph or by completing the square.

Example: Solve

Thenor