Chapter 1 - Review Exercises - Page 163: 56

If $D>0$ there are two real distinct solutions If $D=0$ there is one real solution If $D<0$ there are no real solutions but two imaginary solutions

Discriminant is: $$D=\sqrt{b^2-4ac}$$ If $D>0$ there are two real distinct solutions If $D=0$ there is one real solution If $D<0$ there are no real solutions but two imaginary solutions