Question

a line of best fit is f(x)=-0.86x + 13.5 for the set of points in the table. 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?

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

-5
-2
3
12

Explanation:

Step1: Substitute x value

Substitute \(x = 18\) into \(f(x)=- 0.86x + 13.5\).
\[f(18)=-0.86\times18 + 13.5\]

Step2: Calculate multiplication

First, calculate \(-0.86\times18=-15.48\).
\[f(18)=-15.48 + 13.5\]

Step3: Calculate addition

Then, calculate \(-15.48+13.5=-1.98\approx - 2\).

Answer:

-2