Use the 2 point form to solve the first part: (9-6)/(8-3) = (y-6)/(x-3).
Write the exponential as ln y = ln A + kx.
The 2 points will give you 2 simultaneous linear equations in unknowns ln A and K as follows
ln 9 = ln A + 8k
ln 6 = ln A +3k
Subtraction will eliminate ln A and get you k.
Either equation will then get ln A.
To get the exponential form back you need to get A= eln A.