When $a ne 0$, there are two solutions to (ax^2 + bx + c = 0) and they are

$$x = {-b pm sqrt{texttip{b^2-4ac}{descriminant}} over 2a}.$$

[katex]

\begin{aligned}

a&=b+c \\

d+e&=f

\end{aligned}

[/katex]

[katex]\bar{y}[/katex]

[katex]

\begin{Bmatrix}

a & b \\

c & d

\end{Bmatrix}

[/katex]

[katex]

\begin{cases}

a &\text{if } b \\

c &\text{if } d

\end{cases}

[/katex]

[katex]

\cfrac{2}{1+\cfrac{2}{1+\cfrac{2}{1}}}

[/katex]