Final answer:
The slope -1800 in the equation C = 30600 - 1800q represents the decrease of $1,800 in the college payment account balance after each quarter.
Step-by-step explanation:
The equation C = 30600 - 1800q represents the balance in your college payment account after q quarters, where C represents the current balance and q represents the number of quarters.
The slope of this equation is -1800, which indicates the rate of change of the balance in relation to the number of quarters. In this context, the slope represents the amount by which your college account balance decreases with each passing quarter. For each quarter that passes, the balance drops by $1,800. This slope is crucial because it helps to forecast the balance at any given point in the future, given the number of quarters that have passed.