a) Show that if $f(x)$ and $g(x)$ are functions such that $f(x)$ is $o(g(x))$ and $c$ is a constant, then $c f(x)$ is $o(g(x))$ where $(c f)(x)=c f(x)$
b) Show that if $f_{1}(x), f_{2}(x),$ and $g(x)$ are functions such that $f_{1}(x)$ is $o(g(x))$ and $f_{2}(x)$ is $o(g(x)),$ then $\left(f_{1}+\right.$ $f_{2} )(x)$ is $o(g(x)),$ where $\left(f_{1}+f_{2}\right)(x)=f_{1}(x)+f_{2}(x)$