document.write( "Question 388388: you decide to make a box. You have one piece of plastic with dimensions 15 in x 10 in, with squares cut from the corners to fold up the sides.
\n" ); document.write( "a. Write an equation that represents the volume of the box without a cover.
\n" ); document.write( "b. Graph your equation on graphing calculator
\n" ); document.write( "c. Use a graph to find the dimensions of the box, to the nearest whole numbers, with the maximum volume.\r
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Algebra.Com's Answer #274815 by Earlsdon(6294)\"\" \"About 
You can put this solution on YOUR website!
The piece of plastic is 15\" by 10\".
\n" ); document.write( "The squares cut from each corner are x\" by x\".
\n" ); document.write( "The volume of the box made from folding up the sides after the square corners have been removed can be expressed by \"V+=+x%28B%29\" where B is the area of the bottom of the box and x is the height of the box sides:
\n" ); document.write( "The area of the box bottom can be expressed by:
\n" ); document.write( "\"B+=+%2810-2x%29%2815-2x%29\", so the volume equation becomes:
\n" ); document.write( "\"V+=+x%2810-2x%29%2815-2x%29\"
\n" ); document.write( "\"V+=+x%28150-50x%2B4x%5E2%29\" or...
\n" ); document.write( "\"V+=+4x%5E3-50x%5E2%2B150x\" This is the equation for the volume of the box.
\n" ); document.write( "The graph of this cubic equation is:
\n" ); document.write( "\"graph%28400%2C400%2C-5%2C10%2C-50%2C140%2C4x%5E3-50x%5E2%2B150x%29\"
\n" ); document.write( "From the graph, you can see that the relative maximum (of y, the volume) occurs at about x = 2 (it's really 1.96187390745...), so the dimensions of the square cut-outs would be 2\" by 2\" to obtain the maximum volume.
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