LaTeX.org

I've been muddling around this for a while following what is said on here:
http://www.andy-roberts.net/writing/latex/mathematics_2

However i keep getting this result:
capture01.png
after typing:
\begin{equation}
f(x) = -a{x}^{2} \pm b{x} + c \mathrm{ } \Vert \mathrm{ x, a, b, c } \in\mathbb{R ...

Hi,
My problem seems a simple one but i haven't been able to figure it out.
Here's the table
table-capture.png

And the command:
\begin{table}[ht]
\caption{Nonlinear model results}
\centering
\addtolength{\tabcolsep}{-12pt}
\begin{tabular}{c c c c}
\hline\hline\small{
Capacitor$/pF$ & Measured ...

Hi,
I'm new to latex and after ages of reasearching i can't seem to find out how to have an even format, heres the picture:
integration.png
Now the circle intergral is somewhat too small. Is there a way to make it larger?

Here is the line:
{\oint} \vec{E} \cdot \mathrm{d}\vec{A} &=& \frac{Q ...