Let $a=g(x).$ Iet $g^{-}(x)$ be continuous over an interval $[$a$,$ t$]$ and let $f(x)$ be continuous over the range of $g(x),$ Identify the substration rule for the definite integral.

${\displaystyle \underset{a}{\overset{s}{}}}f(g(x))g^{\text{'}}(x)dx={\displaystyle \underset{a}{\overset{b}{}}}f(x)dx$

${\displaystyle \underset{a}{\overset{b}{}}}g(x)g^{\text{'}}(x)dx={\displaystyle \underset{(a)}{\overset{(a)}{}}}f(x)dx$

${\displaystyle \underset{0}{\overset{b}{}}}f(e^{\text{'}}(x))g(x)dx={\displaystyle \underset{(0)}{\overset{(0)}{}}}f(iv)dv$