To find the equation of the line hrough the points (0, 5) and (5, 1), we first find the slope using the info on the points, via the formula for slope:
slope = (y2 - y1) / (x2 - x1)
in our case:
slope = (1 - 5) / (5 - 0) = -4 / 5
Now we use it in the slope-intercept form of a line:
y = m x + b
(where m is the "slope" and b is the y-intercept)
then, since in our case, the slope is -4/5 and the y intercept occurs at (0, 5) (from the given point), we build the equation as:
y = -4/5 x + 5