Let's consider your title's topic with a little more challenging input with integrals.
I find Andrew's \eqbreak in \begin{aligned} ... \end{aligned} in table as a more configurable option here.
Your table goes well with Henri's example but if you get integrals and other challenging operators eqbreak is useful.
Changes
- no
booktabs with vertical lines [Zarko]
- Andrew's
\eqbreak for challenging operators etc integrals
\bgroup\def\arraystretch{1.5} ... \egroup for more space in cells
- Explicitly
\begin{aligned}...\end{aligned} [Andrew2]
Your example with integrals
\documentclass[english]{article}
\pagestyle{empty}% for cropping
\usepackage{amsmath, amsfonts,rotating}
\usepackage{physics}
% http://tex.stackexchange.com/a/139450/13173
% http://tex.stackexchange.com/a/324197/13173
\newcommand{\eqbreak}[1][2]{\\&\hskip#1em}
\begin{document}
\bgroup
\def\arraystretch{1.5}% 1 is the default, change whatever you need
\begin{tabular}{| l | p{0.7\linewidth} |}
\hline
Hardware & Rekensom \\ \hline
6506E &
$\begin{aligned}
1 - (1 - 0.9999909)^2 \eqbreak[-2] \times \int\limits_{-\infty}^{+\infty} A x \cdot \int\limits_{-\infty}^{+\infty} B y \times Z \alpha \, \text{dy} \, \text{dx} \\ &= 0.99999999991 \cdot 100\,\% \\
&= 99.9999999917\,\%
\end{aligned}$ \\ \hline
6509E &
$\begin{aligned}
1 - (1 - 0.9999885)^2 &= 0.99999999986 \cdot 100\,\% \\
&= 99.9999999868\,\%
\end{aligned}$ \\ \hline
\end{tabular}
\egroup
\end{document}
Output

Limitations
$. – Henri Menke Apr 06 '14 at 18:51\documentclass{...}, the required\usepackage's,\begin{document}, and\end{document}. That may seem tedious to you, but think of the extra work it represents for TeX.SX users willing to give you a hand. Help them help you: remove that one hurdle between you and a solution to your problem. – jub0bs Apr 06 '14 at 19:02