The number (in millions) of single digital downloads annually in the United States each year during $2003-2005$ can be modeled by the polynomial $45 x^{2}+95 x,$ where $x$ is the number of years since 2003 . (Source: Recording Industry Association of America).
a. Find the number of single digital downloads in $2005 .$ To do so, let $x=2$ and evaluate $45 x^{2}+95 x$
b. Use this expression to predict the number of single digital downloads in 2009
c. Factor the polynomial $45 x^{2}+95 x$