Hi there! f(18) makes the value of x 18 and x is the number of movies watched in 1 month. Therefore, A and C are eliminated because we’re talking 18 movies, not 18 months. B is also out, because Kelsey would pay more than $27 a month for the service, especially with the service fee. 18 * 1.50 is 27 and 27 + 12.50 is 39.50. Kelsey spends $39.50 a month watching 18 movies per month. The answer is D.

4 0

2 years ago

The graph of the function f(x) = (x - 3)(x + 1)

djyliett [7]

Answer:

The graph is positive and decreasing for all real values of x where x < -1

Step-by-step explanation:

we have

$f(x)=(x-3)(x+1)$

The function is a vertical parabola open up

The roots (x-intercepts) are x=3 and x=-1

The vertex is the point (1,-4 ) is a minimum

using a graphing tool

see the attached figure

we know that

In the interval (-∞,-1) ---> the function is positive and decreasing

In the interval (-1,1) ---> the function is negative and decreasing

In the interval (1,3) ---> the function is negative and increasing

In the interval (3,∞) ---> the function is positive and increasing

therefore

The graph is positive and decreasing for all real values of x where x < -1

8 0

2 years ago