Here are some guidelines for when writing LaTeX
Writing equations
All equations should be written around the \begin{align*} environment, as follows:
\begin{align*}
x = \frac {-b \pm \sqrt{b^2 -4ac}} {2a}
\end{align*}Concatenated enumerates
\begin{enumerate}[label=(\alph*)]
\item For the given points $A$ to $G$, determine in which instants:
\begin{enumerate}[label=(\roman*)]
\item The car is at rest
\item The car is neither accelerating nor decelerating
\item The car changes direction
\end{enumerate} \marginpar{[6]}
\end{enumerate}