monotonic functions

Among the following functions, let a be the number of functions that are monotonically increasing, let b be the number of functions that are monotonically decreasing, and let c be the number of functions that are neither monotonically increasing nor monotonically decreasing. what is a,b, and c?

$\begin{align*} y &= x^4 \\ y &= \log_{\frac{1}{2}} x \\ y &= x^2 - 2x \\ y &= \frac{1}{x^2} \\ y &= -\frac{1}{\sqrt{x}} \\ y &= \sqrt[3]{x + 4} \\ y &= 11^{-x} \\ y &= 5 - 3x \end{align*}$ 
 

thanks