Answer
LHS $=$ RHS $=\frac{l b}{f t^3}$
Work Step by Step
$\begin{gathered}\frac{\partial p}{\partial x}=\mu \frac{\partial^2 u}{\partial y^2} \\ \frac{\partial p}{\partial x}=\frac{\frac{l b}{f t^2}}{f t}=\frac{l b}{f t^3}[\mathrm{RHS}] \\ \mu \frac{\partial^2 u}{\partial y^2}=\frac{l b \cdot s}{f t^2} \frac{\frac{f t}{s}}{f t^2}=\frac{l b}{f t^3}[\text { LHS }] \\ \text { LHS }=\text { RHS }=\frac{l b}{f t^3}\end{gathered}$
