I'm simply horrible at algebra, pls a friend out guys : ~)

Consider the function f(x)=−2/3x+5 . what is f(1/2) ? enter your answer, as a simplified fraction, in the box. f(1/2)=

If the cost to mail a package is an initial $5 and $0.28 for every pound the total cost to mail a package was $11.27, how much did the package weigh?

What is the value of x in the equation (2)3) (x+6)= -18 a. -36 b. -33 c. -24 d. -18