First, find the slope using the equation, y2 - y1 / x2 - x1
1-5 / 4 - - 4 = -4/8 = -1/2
plug this into slope intercept form
y = -1/2x + b
Next use one of the points to find b using point-slope form. I will use (4,1)
y - y1 = m ( x - x1)
y - 1 = -1/2 (x - 4)
y -1 = -1/2x + 2
+1 +1
y = -1/2x + 3 is your equation
