How do you solve this?

A warehouse is packing materials to ship out to a customer. A small box has the dimensions of x inches, (x+ 2) inches and (2x) inches. Where x is the length in inches of width. A large box has the dimensions of (x+5) inches, (x + 7) inches and (3x) inches.

*Recall that Volume = (Length)(Width)(Height)

Part 1: Write an expression that represents the dimensions of the small box.

Part 2: Write an expression that represents the dimensions of the large box.

Part 3: What is the difference in the volumes of the two boxes? Show or explain or work.

(I think I understand parts 1 and 2 but I'm definitely struggling with part 3)

1 Answer
Feb 10, 2017

The difference in volume is x(x2+32x+105) cubic inches.

Explanation:

I'm going to do all three parts just so that you can compare your work.

Vsmall=x(2x)(x+2)=x(2x2+4x)=2x3+4x2

Vlarge=(x+5)(x+7)(3x)=(x2+12x+35)(3x)=3x3+36x2+105x

Now, subtract the largest volume from the small volume to get the difference in volume. Call the difference D.

D=VlargeVsmall

D=3x3+36x2+105x(2x3+4x2)

D=3x3+36x2+105x2x34x2

D=x3+32x2+105x

D=x(x2+32x+105)

This cannot be factored any further.

Hopefully this helps!