How do you factor #3r^3-192r#?
1 Answer
Jan 4, 2017
Explanation:
The first step is to take out a
#color(blue)"common factor"# of 3r
#rArr3r(r^2-64)# We now have a
#color(blue)"difference of squares"# inside the bracket, which factorises in general as.
#color(red)(bar(ul(|color(white)(2/2)color(black)(a^2-b^2=(a-b)(a+b))color(white)(2/2)|)))#
#"here " a = r" and " b=8#
#rArrr^2-64=(r-8)(r+8)#
#"Pulling it all together gives"#
#3r^3-192r=3r(r-8)(r+8)#
