Will mark brainiest if right only answer if your confident

For problems 29 - 31 the graph of a quadratic function y=ax^2 + bx + c is shown. tell whether the discriminant of ax^2 + bx + c = 0 is positive, negative, or zero.

The roots of the function f(x) = x2 – 2x – 3 are shown. what is the missing number?

What is the similarity ratio of a cube with volume 729m^3 to a cube with volume 3375 m^3