Can someone explain to me what i am supposed to do to get the answer? i'm not sure if i use trig sin or am i missing something

What is the value of the expression below? (81^2)^1/8

Which fraction is not equivalent to 8/12 a. 2/3 b. 24/36 c. 4/10 d. 6/10

An initial investment of $100 is now valued at $150. the annual interest rate is 5%, compounded continuously. the equation 100e0.05t = 150 represents the situation, where t is the number of years the money has been invested. about how long has the money been invested? use your calculator and round to the nearest whole number. years