Question

a line of best fit is $f(x)= - 0.98x + 13.5$ for the set of points in the table.

x	f(x)
3	10
5	10
6	8
7	9
8	5
9	6

using the equation for the line of best fit, what is a good approximation for the value of the function, f(x) when x = 18?
-5
-2
3
12

Explanation:

Step1: Identify the line - of - best - fit equation

The line of best fit is $f(x)=-0.98x + 13.5$.

Step2: Substitute $x = 18$ into the equation

$f(18)=-0.98\times18 + 13.5$.
First, calculate $-0.98\times18=-17.64$.
Then, $f(18)=-17.64 + 13.5=-4.14\approx - 4$. The closest option is - 5.

Answer:

-5