Answer
a) $\left[F L^{-1}\right] $
b) $\left[F L^{-3}\right]$
c) $[F L]$
Work Step by Step
$\begin{aligned} a) & \frac{d P}{d x} \doteq \frac{F}{L} \doteq F L^{-1} \\\\ b) & \frac{d^3 P}{d x^3} \doteq \frac{F}{L^3} \doteq {F L^{-3}} \\\\
c) &\int Pdx=F L
\end{aligned}$
