Question

Please help!!! 30 points!!!

1) The function f(x)=0.11x +43 relates how much Derek pays for phone service, f(x), to the number of minutes, x, used for international calls in a month. What is the value and meaning of f(320)?
A) $78.20;This is the amount Derek pays for 320 months of service.
B) $78.20; This is the amount Derek pays for 320 minutes of international calls.
C) $92.50; This is the amount Derek pays for 320 months of service.
D) $92.50; This is the amount Derek pays for 320 minutes of international calls.

2) Find the ordered pairs for the x- and y-intercepts of the equation 2x-6y=24 and select the appropriate option below.
A) The x-intercept is (2,0); the y-intercept is (0,-6).
B) The x-intercept is (0,2); the y-intercept is (-6,0).
C) The x-intercept is (12,0); the y-intercept is (0,-4).
D) The x-intercept is (0,12); the y-intercept is (-4,0).

Answer 1

#1,
Plugging in 320, we get the answer as 78.20. f(320) = 0.11(320) + 43.
This eliminates answer choices C and D.
Now, in the question it says that x is minutes. 320 is substituted in place of x, meaning that the price is for 320 minutes.

Answer is B.

#2,
x-intercept can be found when y = 0
2x -6(0) = 24
2x = 24
x = 12
x-intercept is (12,0)

y-intercept can be found when x = 0
2(0) - 6y = 24
-6y = 24
y = -4
y-intercept is (0,-4)

Answer is C.