The Discriminant (Online Tutorial #26)

The Discriminant

What is the Discriminant??

This is part of the quadratic formula that informs us how how many solutions the quadratic equation will have.

Why is it Important??

When solving using the quadratic formula, you will know how many solutions you should have.

-a positive answer = 2 real roots

-a zero answer = 1 real root

-a negative answer = no real roots

Given the quadratic 4x²+5x - 1

• a = 4 b = 5 c = -1

• Enter into the discriminant formula

• 5²-4(4)(-1)

• 25 + 16 = 41

• This means that the quadratic has 2 real solutions.

Discriminant

Determines the number of zeros (x-intercepts) a quadratic has.

Given the quadratic 4x²+12x + 9

• a = 4 b = 12 c = 9

• Enter into the discriminant formula

• 12²-4(4)(9)

• 144 - 144 = 0

• This means that the quadratic has 1 real solutions.