The slope-intercept form: y = mx + b.
m - slope, b - y-intercept
[tex]m=\dfrac{y_2-y_1}{x_2-x_1}[/tex]
We have the points (0, 75) → y-intercept (b = 75), and (7, 40).
Substitute the coordimates of the points to the formula of a slope:
[tex]m=\dfrac{40-75}{7-0}=\dfrac{-35}{7}=-5[/tex]
Answer: y = -5x + 75.
