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

II only

Explanation:

The positive leading coefficient and even degree of f(x) tell you its graph is U-shaped and opens upward.

If there is an interval where the function is negative, it must lie between the two x-intercepts. The graph will be above the x-axis (f(x) > 0) for x-values outside that interval.

The only reasonable answer choice is ...

II (-1, 4) . . . . only