Question

How can we use the discriminant to determine the types of zeros a quadratic equation will have?

Answer 1

The discriminant is calculated as b^2 - 4ac.

If the discr. is +, you'll have 2 unequal real roots.
If the discr. is 0, you'll have 2 equal, real roots (repeated root)
If the d. is -, you'll have 2 different, complex roots.