# How do use the discriminant to find all values of c for which the equation #2x^2-x-c=0# has two real roots?

##### 1 Answer

Apr 3, 2017

You first write out the discriminant

#### Explanation:

We know the values of

For two (unequal) real roots

Below is the graph of the borderline case, where

graph{2x^2-x+1/8 [-10, 10, -5, 5]}

You will see, that as

Here

graph{2x^2-x-1 [-10, 10, -5, 5]}