Question

Which equation represents an exponential function that passes through the point (2.80)?
A f(x) = 4(x)^5
B f(x) = 5(x)^4
C f(x) = 4(5)^x
D f(x) = 5(4)^x

Answer 1

Answer:

B f(x) = 5(x)^4

D f(x) = 5(4)^x

Step-by-step explanation:

We want to find the exponential function that represents a function passing through (2,80).

All we need to do is quickly substitute the point into the functions and select the function it satisfies.

For A f(x) = 4(x)^5, we have

$f(2) = 4(2)^5 = 4 \times 32 \ne80$

For B f(x) = 5(x)^4, we have

$B f(2) = 5(2)^4 = 5 \times 16 = 80$

For C f(x) = 4(5)^x, we have:

$f(2) = 4(5)^2 = 4 \times 25 \ne80$

For D f(x) = 5(4)^x, we have;

$f(2) = 5(4)^2 = 5 \times 16 = 80$

Options B and D are correct