$${\left( {1217} \right)_8}$$ is equivalent to

$${73_x}$$ (in base $$-$$ $$x$$ number system) is equal to $${54_y}$$ (in base $$-y$$ number system), the possible values of $$x$$ and $$y$$ are

Assuming all numbers are in $$2's$$ complement representation, which of the following numbers is divisible by $$11111011?$$

The $$2's$$ compliment representation of the decimal value $$-15$$ is