Question

Which of the following is false about the function y = negative 4 times 3 Superscript x? a. the function decreases c. if the value of x increases by 3, the value of y will triple. b. the function has a y-intercept of (0, -4) d. the function contains the point (1, -12) Please select the best answer from the choices provided

Answer 1

c. if the value of x increases by 3, the value of y will triple

Explanation:

Let's compare values for x and (x+3).

y1 = -4·3^x

y2 = -4·3^(x+3) = -4·(3^x)(3^3)

So, when x increases by 3, the ratio of the new value to the old one is ...

y2/y1 = -4·3^x·3^3/(-4·3^x)

y2/y1 = 3^3 = 27

When x increases by 3, the value of y is multiplied by 27, not 3.

__

The attached graph shows you the function is decreasing, has a y-intercept of -4, and contains the point (1, -12).