A manufacturer of shipping boxes has a box shaped like a cube. The side length is

(5a + 4b). What is the volume of the box in terms of a and b? Show your work.
(5a+4b)^3 =(5a+4b)(5a+4b)(5a+4b) =(25a2+40ab+16b2)(5a+4b) = 125a^3 + 100a^2b + 200a^2b + 160ab^2 + 80ab^2 + 64b^3 = 125a^3 + 300a^2b + 240ab^2+ 64b^3

is this correct as an answer?

2 answers

Alexa, I answered this for you yesterday

http://www.jiskha.com/display.cgi?id=1455679992

Your expansion is correct, but as I stated yesterday , why not just leave the answer as
Volume = (5a+4b)^3

For any given value of a and b, it would be so much easier to find the volume from the factored form, than from the expanded form.
okay..But why does it say show your work? how would I show it?