I'm given the equation S = L(1 - e^(-kt))

I am asked to write S as a function of t when L = 100, S = 25 when t = 2

So would my final answer just have S and t as variables? Or have S, t and L as variables?

Ended up with S = 100(1 - e^((ln(3/4)/2)*t)

Or is the actual answer S = L(1 - e^((ln(3/4)/2)*t)

Your final answer is correct.