Question

What are the x-intercepts of the graph of the function f(x) = x2 + 5x − 36?

(−4, 0) and (9, 0)
(4, 0) and (−9, 0)
(−3, 0) and (12, 0)
(3, 0) and (−12, 0)

Answer 1

Factor: x^2 + 5x − 36 = (x + 9)(x − 4).
Set = 0 → x = −9 or x = 4.

So the x-intercepts are (4, 0) and (−9, 0).