Question

It’s confusing on how they worded it to me

Answer 1

You're looking for the equation of the line through the two yellow points, whose coordinates are (4, 0) and (8, 9).

Compute the slope:

(9 - 0) / (8 - 4) = 9/4

Using the point-slope formula, the equation of the line is

y - 0 = 9/4 (x - 4)

or

y = 9x/4 - 9