Question

The equation for the line of best fit is f(x) ≈ 1.8x − 5.4 for the set of values in the table.

A 2-column table with 7 rows. The first column is labeled x with entries 4, 5, 6, 6, 8, 9, 10. The second column is labeled f(x) with entries 5, 2, 5, 6, 8, 7, 18.

Using the equation for the line of best fit, what is a good approximation for x when f(x) = 30?

14
20
45
54

Answer 1

Set 1.8x − 5.4 = 30. Then 1.8x = 35.4, so x = 35.4 / 1.8 ≈ 19.67 ≈ 20.