Okay. So t is in the parenthesis of the equations and represents the number of years after 1950. In this case, the first, second, third, and the seventh tile won't work, because those numbers are too big to be applicable as years. The number of vinyls sold each year would be put behind the equal sign. If you solve it correctly, here are your answers starting from the top:
1. f(8) = 68,594
2. f(11) = 91,299
3. f(2) = 38,720
4. f(17) = 161,743