Im not good with finding the rule

Three times the sum of a number and seven is negative thirty-six. what is the number?

What’s the answer ? use the picture to see the problem

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.