ANSWER
The discriminant is 384. Because the discriminant is greater than 0 and is not a perfect square, the two roots are real and irrational.
EXPLANATION
The given quadratic equation is:

We compare this equation to:

We have a=-3,b=-18, and c=5.
The discriminant of a quadratic equation is calculated using the formula:

We plug in the values to obtain:


Simplify:

The discriminant is greater than zero, hence there are two distinct real roots.
Since 384 is not a perfect square, the roots are irrational.