The water level in a reservoir is changing at a rate described by the equation 4x−3y=15, where x represents the time in years and y represents height in inches. What is the rate of change of water in the reservoir?
34 inch decrease per year
3 fourths inch decrease per year
34 inch increase per year
3 fourths inch increase per year
43 inch increase per year
4 thirds inch increase per year
43 inch decrease per year