This problem is incomplete, but I think I know the probable question. Normally, you should have been given the target number of the company's video stores, so that you can replace the value of y and solve for x. Once you solve for x, you add this to year 1990 then you can solve for the year at which you can reach your target value. Suppose y = 3500 stores.
3500 = -264x + 4682
3500 - 4682 = -264x
-1182 = -264x
x = 4.48 years
Technically, that is equal to 4 years. Hence, the year would be 1990+4 = 1994.