Answer:
y = -3x + 8
Explanation:
I like to recommend this particular method for finding the slope of a line through two given points:
Notice that if we move from (3, -1) to (5, -7), the horizontal distance covered (the "run") is 2 and the vertical change (the "rise") is -6. Thus, the slope is m = rise / run = -6 / 2, or -3.
Starting with y = mx + b, replace y with -7 and x with 5, and m with -3:
-7 = -3(5) + b ... we must find b.
-7 = -15 + b yields b = 8
and so the equation of this line is y = -3x + 8.