How do you factor #9m^2-144#?

1 Answer
Mar 6, 2017

Answer:

#9(m-4)(m+4)#

Explanation:

The first step in factorising is to take out any #color(blue)"common factor"#

#rArr9m^2-144=9(m^2-16)larr" common factor of 9"#

Now #m^2-16" is a " color(blue)"difference of squares"# and is factorised, in general, as shown.

#color(red)(bar(ul(|color(white)(2/2)color(black)(a^2-b^2=(a-b)(a+b))color(white)(2/2)|)))#

#"For " m^2-16to a=m" and " b=4#

#rArrm^2-16=(m-4)(m+4)#

Putting it all together gives.

#rArr9m^2-144=9(m-4)(m+4)#