Answer
a. "take the cube root, subtract 5 and divide by 3"
b. $f(x)=(3x+5)^{3},\displaystyle \quad f^{-1}(x)=\frac{x^{1/3}-5}{3}$
Work Step by Step
$a.$
Reverse the order and perform opposite operations:
"take the cube root,
subtract 5 and
divide by 3."
$b.$
$f(x)=y=(3x+5)^{3} \quad\left[\begin{array}{lll}
x & = & (3y+5)^{3}\\
x^{1/3} & = & 3y+5\\
x^{1/3}-5 & = & 3y\\
\dfrac{x^{1/3}-5}{3} & = & y=f^{-1}(x)
\end{array}\right]$
