Consider the following multiplexer where $$10, 11, 12, 13$$ are four data input lines selected by two address line combinations $${A_1}\,{A_0} = 00,01,10,11$$ respectively and $$f$$ is the output of the multiplex (or). $$EN$$ is the Enable input.

The function $$f(x,y,z)$$ implemented by the above circuit is

The decimal value $$0.25$$

Sign extension is the step in

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