Graph y = log5x and its inverse.

We graph y = log 5x using Google Sheets and get the inverse using rearrangements and simplification
y = log 5x10 ^ y = 5xx = 1/5 10^yy = 1/5 * 10^x
we also graph the inverse using Google Sheets. The graphs are attached below

Option 2 - f(x)=-2

Step-by-step explanation:

Given : A line of best fit is f(x) ≈ −0.86x + 13.5 for the set of points in the table.

2    12

3    10

5    10

6     8

7     9

8     5

9     6

To find :  What is a good approximation for the value of the function, f(x), when x = 18?

Solution :

We have given the function,

The best fit for the value x=18, f(x) is

Approximately, For the value of x=18, f(x)=-2

Therefore, Option 2 is correct.