229k views
1 vote
A box has a width 9 inches less than its height and a length 7 inches more than its height.

a. If h is the height of the​ box, write a polynomial that represents the volume of the box.
b. Use this polynomial to calculate the volume for h​ = 17 inches.

1 Answer

6 votes
So everything in this problem is in terms of height (h). We'll abbreviate width to w and length to l and volume to v

l=h+7
w=h-9

a.
volume is height x width x length

v=h*(h+7)*(h-9)

now we have to multiply these values

h*(h+7)=h^2+7h

(h^2+7h)*(h-9)=h^3-9h^2+7h^2-63h=h^3-2h^2-63h

b.
now we plug in h=17
v=17^3 -2(17)^2 -63(17) = which comes out to 2686

note: **i suggest going through these steps on your own mostly because it's late and i'm tired and that seems like an awfully large number so you may want to check it
User Abdulmalek Dery
by
7.9k points