A rectangular box is twice as long as it is wide. The height of the box is 3 feet less than the width. If the box is x feet wide, what polynomial represents its volume in cubic feet?

A.

B.

C.

D.

Question

A rectangular box is twice as long as it is wide. The height of the box is 3 feet less than the width. If the box is x feet wide, what polynomial represents its volume in cubic feet?

A. 

B. 

C. 

D.

anonymous · Answer

A. 4x-3
B. 2x3
C. 2x2 -6x
D. 2X3-6X2

anonymous · Answer

Volume of a cuboid= l * b * h
Width = x
Length = l = 2x
Height = h = x - 3
Now substitute the values in the formula.
$$2x \times x \times (x-3)$$
Can you solve it now?

anonymous · Answer

4X-3

anonymous · Answer

No,
$$2x ^{2} ( x - 3) $$
Therefore, it's $$2x ^{3} - 6x ^{2}$$

e.mccormick · Answer

Tip:  Volume is always a cubic equation, so it must have something to the third power.  In a question like this, little facts light that can eliminate some of the choices and make it easier to get to the right answer.

anonymous · Answer

OH I get it now, thanks a lot

anonymous · Answer

@e.mccormick  Indeed, if there are choices that is. :-)

e.mccormick · Answer

@Jas9420  Yep.  And it can also help you see if you did a calculation right.  if you multiply out a volume and don't get a cubic value, then you made a mistake somewhere!