Useful links for Mathematics Stack Exchange:

How to ask a good question.

In particular, to increase your chances of having your question answered instead of closed:

1. explain the context of your problem (where is it from),
2. state your problem clearly,
3. show your attempt at solving your problem, and
4. explain where you are stuck or confused.

DO NOT simply write a question with "PLZ HELP!"

MathJax basic tutorial and quick reference

To get started, try:

1. putting $ on either side of math, as in $1+2$
2. using ^ for superscripts and _ for subscripts, with { } to group multiple characters, as in $3^{1+2}$ for $3^{1+2}$
3. using \frac{ }{ } for fractions, as in $\frac{4}{5}$ for $\frac{4}{5}$
4. using \alpha, \beta, ... for greek letters

$$\frac{ x_{n+1} + \alpha }{ x_n + \beta } = \gamma^3$$ would render like this:

$$\frac{ x_{n+1} + \alpha }{ x_n + \beta } = \gamma^3$$

$\LaTeX$