text: # using polynomials
  
  • Mar 27th 2009, 12:18 AM
  vidalex
  using polynomials
  The problem states:The volume of the box is 630in^3. The height is 4 in more than the width, the length is 1 in more than than width.What is the width?
  
  I started by forming the equation based on l*w*h=v so,
  
  (1+w)(4+w)(w)=630 and i combined to get
  
  w^3+5w^2+4w=630
  
  And from this point I'm stuck
  • Mar 27th 2009, 12:47 AM
  craig
  Your work so far is correct, rearranging the formula you have above will give you the following cubic equation:
  
  \$\displaystyle w^3 + 5w^2 + 4w - 630 = 0\$
  
  Have you been taught how to solve cubic equations?
  • Mar 27th 2009, 01:02 AM
  vidalex
  No this is an extra credit problem for this unit. We've covered how to find zeros but this problem has me stumped.
  
  Quote:
  
  Originally Posted by craig
  Your work so far is correct, rearranging the formula you have above will give you the following cubic equation:
  
  \$\displaystyle w^3 + 5w^2 + 4w - 630 = 0\$
  
  Have you been taught how to solve cubic equations?
  
  • Mar 27th 2009, 04:26 AM
  stapel
  If you're using graphing calculators in your class, maybe you're expected to use that to find where the polynomial crosses the x-axis...?