Best explained and correct answer gets

The answer is D, here’s why:

You know the slope-intercept form is y=mx+b
mx being the slope and b being the y-intercept.

y=-4/7x + 9 is already in that form.

A is not the answer because the y is supposed to be by itself.
B is not the answer because again, the y is not by itself.
C is not the answer because the y is also not by itself.

In the slope-intercept form, the y must be by itself and the slope (mx) and the y-intercept must be on the other side.

Hope this helps.