Aline 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?

The question asks us to calculate the value of the fuction that best fits the set of the points in the table when x = 18. We know that the function is: f ( x ) = - 0.86 x + 13.5. We have to put the value ( x = 18 ) in the function: f ( 18 ) = - 0.86 * 18 + 13.5 = - 15.48 + 13.5 = - 1.98. When x = 18, f ( x ) = - 1.98.

The answer would be -3.9> -4.5