The answers are f = 2 and p = -2
Start by getting the term with the exponent on one side

take the log of both sides

There is a log rule that says we can bring down the exponent

Solve for x

5x=6.64
answer: x=1.33
40 = n-.40n
40 =n(1-.4)
40 = n(.6
divide by .6 on each side
40/.6 =n
n=66 2/3