# The Quadratic Formula

There is a nice formula for finding the roots (zeroes,
”where the graph crosses

the x-axis”). The idea is that given a quadratic polynomial :

We can say the roots occur at:

We could plug this back into our equation and see that we do indeed get zero,

but for now, I will ask you to just believe me.

**Example:**

Find the roots of the polynomial y = 2x^{2} − 6x + 4.

To do this, we see we can simply apply the given formula to get:

We notice that plugging in the values of x = 2 and x = 1 do indeed give us zero,

this makes us happy.

Prev | Next |