Answer:
-1/3
Explanation:(if treasure of change is "rate of change")
Equation of a line: mx + b
m=-1/3: slope
b: y-intercept
^Whenever working with an equation of slope/rate of change the above variables have specific meanings.
Slope is another term for rate of change so the rate of change would be -1/3.
m=-1/3=slope/rate of change
b=4=y intercept