# How to express boolean polynomials by special form

If I have boolean polynomials like

```
x_1 * x_2 + x_1*x_3* x_5 + x_3 + x_7*x_2
```

then given a variable `x_1`

, how can I represent it as

```
x_1 * (x_2 + x_3*x_5) + (x_3 + x_7*x_2)
```

using Sage?

In general, I want to find a way to represent a form of `a * x_1 + c`

,
where `a`

is the linear combination of multiples of `x_1`

and `c`

is the rest polynomial.

Welcome to Ask Sage! Thank you for your question!