Weird question wording. I take it should mean that this is a quadratic equation with solutions of x = -5 and x = 8. Then these are the factors: (x+5) and (x-8). So
(x+5)(x-8) = 0 is the equation because x = -5 and x = 8 can make left-side equal to 0. But we expand so it becomes x² - 3x - 40 = 0
