\[ a^2 + 3ax - x^2 \]

\[ \frac{abc}{xyz} \]

\[ \{ 1,2,3 \}, \mathbb{N}, \mathbb{Z}, \ldots \]

\[ \alpha,\beta,\gamma,\ldots,\omega \]

\[ \sum, \int, \lim \]

\[ \sqrt{\cdot} \]

\[ \alpha \vec{x} + \beta \vec{y} \]

\[ \left( \begin{array}{cc} 1 & 2 \\ 3 & 4 \end{array} \right) \cdot \vec{x} = \left( \begin{array}{c} -3 \\ 5 \end{array} \right) \]

\[ \int_a^b f(x) \, dx \]