How do you factor #4a^3-64a#?

1 Answer
May 7, 2016

Answer:

#4a(a-4)(a+4)#

Explanation:

4 is a factor of both 4 and 64

#a# is a factor of both #4a^2" and "64a#

Factor out #4a# giving:

#4a(a^2-16)#

But 16 is the same as #4^2#

#4a(a^2-4^2)#

'...........................................
compare to the example #y^2-z^2=(y-z)(y+z)#
'..............................................

#color(brown)(4a(a^2-4^2))color(blue)(" "->" "4a(a-4)(a+4)#