Question

Which function has an asymptote at x= 39

Answer 1

The correct answer is b. f(x) = log7(x-39)

Answer 2

option B :
`f(x)= log_7(x-39)`

Explanation:

(a)
`f(x) = 7^(x-39)`

For exponential function , there is no vertical asymptotes

General form of exponential function is

`f(x) = n^(ax-b)+k`

`f(x) = 7^(x-39)`

In the given f(x) the value of k =0

So horizontal asymptote is y=0

(b) lets check with option

`f(x)= log_7(x-39)`

To find vertical asymptote we set the argument of log =0 and solve for x

Argument of log is x-39

x-39=0 so x=39

Hence vertical asymptote at x=39