the line through (3, 7) and (-1, 4)
slope of a line through 2 points
m = (y2 - y1) / (x2 - x1)
m = (4 - 7) / (-1 - 3)
m = -3 / -4
m = 3/4
b = y - mx
b = 7 - 3/4 (3)
b = 7 - 9/4
b = 28/4 - 9/4
b = 19/4
The equation is y = 3/4 x + 19/4
y = 0.75x + 4.75