Explanation of quadratic equation

The Quadratic Formula. The quadratic equation has the solutions

Explanation

Consider the general quadratic equation

with . First divide both sides of the equation by a to get

which leads to

Next complete the square by adding to both sides

Finally we take the square root of both sides:

or

We call this result the Quadratic Formula and normally write it

The plus-minus sign states that you have two numbers and .