Question

The minimum value of f(x) = x3 – 3x2 – 9x + 2 on the interval [–4, 0] is

–74

–25

2

7

Answer 1

-74

Explanation:

Graph the function. See attached picture. Between the interval where -4 > x < 0, the graph rises up to a peak and descends back down when x = 0. This means the minimum value will be where x = -4.

Substitute x = -4 into the equation.

f(-4) = (-4)^3 -3(-4)^2 - 9(-4) + 2

f(-4) = -64 -3(16) +36 + 2

f(-4) = -64 - 48 + 36 + 2

f(-4) = -74