You are going to drive from home to your destination in a car that can get 40 miles per gallon of gasoline. Your gas tank holds 15 gallons of fuel. Gas costs $2.00 per gallon. How many times would you have fill up your tank if each time you filled it up completely and how much would it cost to drive to your destination?

x=-1 is a maximum vaue.

Step-by-step explanation:

To find the minimum and maximum values of the function f(x), we're going to derivate it:

f(x) = –5x^2 – 10x + 6 ⇒ f'(x) = -10x - 10

The points where f'(x) is zero, could be a maximum or a minimum. Then:

f'(x) = -10x - 10 = 0 ⇒ x=-1

Now, to know if x=-1 is a maximum or a minimum, we need to evaluate the original function for x when it tends to -1 from the right and from the left.

Therefore:

For x=-2:

f(x) = 6 (Positive)

For x=0:

f(x) = 6 (Positive)

For x=-1

f(x) = 11 (Positive)

Given that at x=-1, f(x) = 11, and then it goes down to 6 when x=0, we can say that it's a maximum.