$4.$ Flow Between Plates $(\backslash (\backslash$mathbf$\{25\}\backslash )$ points$)$

A fluid of viscosity $\backslash (\backslash$mu $\backslash )$ flows in the $\backslash ($ x $\backslash )$ direction between $2$ rectangular plates, whose width is large in the $\backslash ($ z $\backslash )$ direction when compared to their distance in the $\backslash ($ y $\backslash )$ direction. If the gap in the $\backslash ($ y $\backslash )$ direction is equal to $6$ d $,$ what is the relationship for:

a$.$ The pressure drop between the inlet and exit?

b$.$ The velocity in the x direction?