MWG $3.$E$\mathrm{.}5$ B Show that if u$($x$)$ is homogeneous of degree one, then h$($p$,$ u$)$ and e$($p$,$ u$)$ are homogeneous of degree one in u $[$i$.$e$.,$ they can be written as h$($p$,$ u$)=$ h$($p$)$u and e$($p$,$ u$)=$e$($p$)$u$].$