Ill mark brainllest if someone gets it right

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

The ratios 3: 9, 4: 12, 5: 15, and 6: 18 are a pattern of equivalent ratios in the ratio table. which is another ratio in this pattern?

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.