Received three problems that r giving me a headache.

The first is R raised to the power 0.75 =24. Does this mean that I should convert 0.75 to 3/4 then multiply 24 by 3 and find the answer raised to the power 4?

(2) R squared +R squared =R cube . How is this possible?

(3) R raised to the power 0.5 - 90=0 Does this mean that I convert 0.5 to 1/2 and then find a number whose square root is 90 and do my calculations from there?