SOLUTION: A box is to be made from a sheet of cardboard 24 inches long and 18 inches wides by cutting squares from each corner and then folding be cut out of each corner if the bottom of the

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: A box is to be made from a sheet of cardboard 24 inches long and 18 inches wides by cutting squares from each corner and then folding be cut out of each corner if the bottom of the      Log On


   



Question 939641: A box is to be made from a sheet of cardboard 24 inches long and 18 inches wides by cutting squares from each corner and then folding be cut out of each corner if the bottom of the box is to have an area of 265 square inches.
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
A box is to be made from a sheet of cardboard 24 inches long and 18 inches wides by cutting squares from each corner and then folding be cut out of each corner if the bottom of the box is to have an area of 265 square inches.
----------
Cut squares x by x
---
(24 - 2x)*(18 - 2x) = 265
4x^2 - 84x + 167 = 0
Solved by pluggable solver: SOLVE quadratic equation (work shown, graph etc)
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 4x%5E2%2B-84x%2B167+=+0) has the following solutons:

x%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca

For these solutions to exist, the discriminant b%5E2-4ac should not be a negative number.

First, we need to compute the discriminant b%5E2-4ac: b%5E2-4ac=%28-84%29%5E2-4%2A4%2A167=4384.

Discriminant d=4384 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28--84%2B-sqrt%28+4384+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%28-84%29%2Bsqrt%28+4384+%29%29%2F2%5C4+=+18.7764726786234
x%5B2%5D+=+%28-%28-84%29-sqrt%28+4384+%29%29%2F2%5C4+=+2.22352732137658

Quadratic expression 4x%5E2%2B-84x%2B167 can be factored:
4x%5E2%2B-84x%2B167+=+%28x-18.7764726786234%29%2A%28x-2.22352732137658%29
Again, the answer is: 18.7764726786234, 2.22352732137658. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+4%2Ax%5E2%2B-84%2Ax%2B167+%29

============
x =~ 2.22 inches