This is homework. please help with the answer for both 11a and 11b :))

If x=-3 is the only x-intercept of the graph of a quadratic equation, which statement best discribes the discriminant of the equation?

For how answer my question this will be the last question can you answer in math subject

1) what is the measure of the exterior angle, ∠uvw ? 2) in triangle man, what is the measure of the exterior angle at n (in degrees)?