# Corresponding value of a parameter

Hello,
I am quite new to Sage and I have the following question.
In my computations I have a quadratic form: **$x^T A x = b $** ,
where the matrix A is defined already as a symmetric matrix, and x is defined as

```
import itertools
X = itertools.product([0,1], repeat = n)
for x in X:
x = vector(x)
print x
```

as all combination of $[0,1]$ repeated n times. I got a set of values for **$b$** and extracted few of them from the set. Now, I need to identify which **$x$** is corresponding to a particular value of **$b$**. Is there any command to do so? If it is possible. Thank you for help.

I don't understand two things. There is no variable

xorbin your code. Furthermore, if you run this code what you get is an empty iteratorWand a vectorwequal to(1,1,...,1)(note that you forgot the line

import itertoolsin your command)My apologies for ambiguity. I have edited the post. Hope it is now clearer.

the whole code with defined previously matrix A looks like this:

@Xenia It is much clearer now. I updated my answer below.