Question

Find the interval in which the function is negative.

f(x)=x²-3x - 4
1. (-∞0, -1)
II. (-1, 4)
HI. (4, ∞)
Oll only
III only
OLI
LIII

Answer 1

Answer: II only: (-1, 4)

Explanation:

x^2 - 3x - 4 is a parabolic function. When you factor the equation, it comes out to f(x) = (x-4)(x+1). Thus, the function as zeros at -1 and 4. Since the a value is positive, the parabola points up. Therefore, if you graph the function, it is negative between -1 and 4, so the answer is II only