Which of the following options results in a graph that shows exponential growth? f(x) = 0.4(3)x f(x) = 3(0.5)x f(x) = 0.8(0.9)x f(x) = 0.9(5)−x

f(x) = 0.4·3^x

Step-by-step explanation:

Exponential growth occurs when the base is greater than 1 and the exponent is an increasing non-negative function of the variable, or when the problem can be cast in that form using the rules of exponents.

Here, in f(x) = 0.4×3^x, the base is 3 (greater than 1), and the exponent of x has a positive coefficient.

a. she will receive a refund of $278.

step-by-step explanation: