## Calculus 10th Edition

$u=x^3-7.$ $y=\sqrt{u}.$
Working from the inside out: Take $x$; cube it and then subtract $7$ from it $\leftarrow$ "inner function." Take $x^3-7$; raise it to the power of $\dfrac{1}{2}\leftarrow$ "outer function." $u=x^3-7.$ $y=\sqrt{u}.$