SOLUTION: The length of a rectangular box is 4 times its height, and its width is 2 ft more than its height. Use the graphing calculator to find the height of the box. Round the answer to t

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: The length of a rectangular box is 4 times its height, and its width is 2 ft more than its height. Use the graphing calculator to find the height of the box. Round the answer to t      Log On


   

Question 1156463: The length of a rectangular box is 4 times its height, and its width is 2 ft more than its height.
Use the graphing calculator to find the height of the box. Round the answer to two decimal places.
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
The length of a rectangular box is 4 times its height, and its width is 2 ft more than its height.
Use the graphing calculator to find the height of the box.
Round the answer to two decimal places.
:
let x = the height
then
4x = the length
and
(x+2) = then width
therefore
vol = 4x * (x+2) * x
v = 4x^3 + 8x^2
At this point it seems we should be given the volume of this box, like v = 64
4x^3 + 8x^2 = 64
4x^3 + 8x^2 - 64 = 0
simplify, divide to 4
x^3 + 2x^2 - 16 = 0
on a graphing calc
+graph%28+300%2C+200%2C+-4%2C+5%2C+-10%2C+10%2C+x%5E3%2B2x%5E2-16%29+
x = 2 is the height