John reads an equal number of pages of a book every week. The graph below shows the number of pages of the book left to read, y, after x weeks: A graph titled John’s Book Reading shows Number of Weeks on the x-axis and Number of Pages Left on the y-axis. The scale on the x-axis shows numbers from 0 to 6 at increments of 1, and the scale on the y-axis shows numbers from 0 to 175 at increments of 25. A straight line joins the ordered pairs 0, 125 and 1, 100 and 2, 75 and 3, 50 and 4, 25 and 5, 0.

HELP ME PLS
Which equation best models the relationship between x and y?

y = −5x + 25
y = −25x + 125
y = −25x + 175
y = −5x + 125