## Calculus 10th Edition

$u=(5x-8).$ $y=u^4.$
Working from the inside out: Take $x$; multiply it by 5 and deduct 8 $\leftarrow$ "inner function." Take $(5x-8)$; raise it to the power of $4\leftarrow$"outer function." $u=(5x-8).$ $y=u^4.$