Answer:
Step-by-step explanation:
y = mx + b
slope m is found as the change in y over the change in x
as y decreases 3 units for a 3 unit increase in x, the slope is -3/3 = -1
The y intercept b is where the plot crosses the y axis, 4 units above the x axis
y = -1x + 4
or
y = 4 - x
