What is the range of the function f(x) = x + |x| if the domain is the set of real numbers ?  

If f(x) = x(4x² - 3), then what is f(sinθ) equal to ?  

What is $\lim\limits_{x \rightarrow 5} \frac{5-x}{|x-5|}$ equal to ?

What is $\lim\limits_{x \rightarrow 1} \frac{x^9-1}{x^3-1}$ equal to ?