How do you simplify #(w^2-16)/w * 3/(4-w)#?
The first thing to notice here is that the numerator of the first fraction can be factored as the difference of two squares, for which you know that
#color(blue)(a^2 - b^2 = (a+b)(a-b))#
In your case, you will get
Another important thing to notice is that you can factor the denominator of the second fraction by using
Your expression will thus be