6. Вычислите $$(x - 1)(x^{25} + x^{24} + x^{23} + ... + x^2 + x + 1) - x^{26}$$ при $$x = 0,93$$.
$$(x - 1)(x^{25} + x^{24} + ... + x + 1) = x^{26} - 1$$
So the whole expression equals $$x^{26} - 1 - x^{26} = -1$$.
Therefore, the answer is -1 irrespective of the value of $$x$$.