What type of equation is b2-4ac?

Answer 1

6

Answer 2

It is not an equation it is an algebraic expression. It doesn't have an equal sign.

b2 - 4ac is part of the solution of the quadratic equation. This part is called the "discriminant"; it determines whether the quadratic equation will have two real solutions (if the discriminant is positive), one (double) real solution (if the discriminant is zero), or two complex solutions (if the discriminant is negative).