Question

a. 0 = -0.3x^2 + 12x + 14
x = -1.134489979... or 41.13448998...
x ≈ 41 (reject x ≈ -1)

The 41st day.

1.) The graph is opening downward, so it has a maximum point near the middle.

2.) x = -b/(2a) = -12/(2 • -0.3) = 20
After 20 days, it reaches a peak.

3.) -0.3(20^2) + 12(20) + 14 = 134

4) The vertex is (20, 134). The x-coordinate represents the day on which the maximum occurs; the y-coordinate represents the maximum value.
(Where are parts e and f?)

a. There are two solutions, because a parabola of this type has two x-intercepts.

b. The solutions are given above.
The solution, x ≈ 41, re