The functions $f$ and $g$ are integrable and ${\displaystyle \underset{2}{\overset{4}{}}}f(x)dx=3,{\displaystyle \underset{2}{\overset{7}{}}}f(x)dx=-7,$ and ${\displaystyle \underset{2}{\overset{7}{}}}g(x)dx=-3.$ Use these to complete parts $($a$)$ through $($f$).$

a$.{\displaystyle \underset{4}{\overset{4}{}}}f(x)dx=$

$($Simplify your answer.$)$

b$.{\displaystyle \underset{7}{\overset{2}{}}}g(x)dx=$

$($Simplify your answer.$)$

c$.{\displaystyle \underset{2}{\overset{7}{}}}4g(x)dx=$

$($Simplify your answer.$)$

d$.{\displaystyle \underset{4}{\overset{7}{}}}f(x)dx=$

$($Simplify your answer.$)$