Can you please solve these problems with explanations?

200 If 1 + 7e-0.5t - 50, solve for t. 8. [-/1 Points] DETAILS Find the values of A and B such that the graph of the exponential function f(t) = Aebt goes through the points (0,8) and (9,3). A= B 9. [-/1 Points] DETAILS Determine the domain of each of the following functions. Enter your answer using interval notation. (a) Domain of In(63-9x) = (b) Domain of logg(x2 - 4) = (c) Domain of log2(x2 + 4) =