# simplifying a symbolic expression

Hi I am really tired of not being able to see that sage says the following expression is zero. Instead it returns the same expression. Please help how to make sure that I get 0 for the calculation. Thank you.

```
q= var('q',domain='positive');
n= var('n',domain='positive');
k= var('k',domain='positive');
x= var('x',domain='positive');
(((q - 1)*x + 1)^n*q^n - ((q^2 - q)*x + q)^n).simplify_full()
((q - 1)*x + 1)^n*q^n - ((q^2 - q)*x + q)^n
```