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 )? -5 -2 3 12

Explanation:

Step1: Substitute \(x = 18\) into the function

Given \(f(x)=- 0.86x + 13.5\), substitute \(x = 18\):
\(f(18)=-0.86\times18 + 13.5\)

Step2: Calculate the product

\(-0.86\times18=-15.48\)
So \(f(18)=-15.48 + 13.5\)

Step3: Calculate the sum

\(-15.48+13.5=-1.98\approx - 2\)

Answer:

-2 (corresponding to the second option)