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 value

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

Step2: Calculate multiplication

Calculate $-0.86\times18=-15.48$.
$f(18)=-15.48 + 13.5$

Step3: Calculate addition

Calculate $-15.48+13.5=-1.98\approx - 2$.

Answer:

-2