document.write( "Question 166560: Hey, I just need help with two word problems.
\n" ); document.write( "1st one: A lot is in the shape of a right triangle. The shorter leg measures 180 m. The hypotenuse is 60 m longer than the length of the longer leg. How long is the longer leg?? \r
\n" ); document.write( "\n" ); document.write( "2nd one: A rectangular piece of cardboard measuring 28 inches by 29 inches is to be made into a box with an open top by cutting equal size squares from each corner and folding up the sides. Let x represent the length of a side of each such square. For what value of x will the volume be a maximum? If necessary, round to 2 decimal places. \r
\n" ); document.write( "\n" ); document.write( "Thank u
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Algebra.Com's Answer #122757 by nerdybill(7384)\"\" \"About 
You can put this solution on YOUR website!
1st one: A lot is in the shape of a right triangle. The shorter leg measures 180 m. The hypotenuse is 60 m longer than the length of the longer leg. How long is the longer leg??
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\n" ); document.write( "Let x = length of longer leg
\n" ); document.write( "then
\n" ); document.write( "x+60 = hypotenuse
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\n" ); document.write( "Applying pythagorean's theorem:
\n" ); document.write( "180^2 + x^2 = (x+60)^2
\n" ); document.write( "180^2 + x^2 = (x+60)^2
\n" ); document.write( "32400 + x^2 = x^2 + 120x + 3600
\n" ); document.write( "32400 = 120x + 3600
\n" ); document.write( "28800 = 120x
\n" ); document.write( "240 meters = x (longer leg)
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\n" ); document.write( "2nd one: A rectangular piece of cardboard measuring 28 inches by 29 inches is to be made into a box with an open top by cutting equal size squares from each corner and folding up the sides. Let x represent the length of a side of each such square. For what value of x will the volume be a maximum? If necessary, round to 2 decimal places.
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\n" ); document.write( "Volume = x(28-2x)(29-2x)
\n" ); document.write( "Volume = x(812-56x-58x+4x^2)
\n" ); document.write( "Volume = x(812-114x+4x^2)
\n" ); document.write( "Volume = 812x-114x^2+4x^3
\n" ); document.write( "Volume = 4x^3-114x^2+812x
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\n" ); document.write( "Taking the derivative:
\n" ); document.write( "4x^3-114x^2+812x
\n" ); document.write( "12x^2-228x+812 = 0
\n" ); document.write( "6x^2-114x+406 = 0
\n" ); document.write( "Solving the above with the quadratic equation we get:
\n" ); document.write( "x = {14.25, 4.75}
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\n" ); document.write( "Solution: 4.75 inches
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\n" ); document.write( "Details of quadratic equation:
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Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation \"ax%5E2%2Bbx%2Bc=0\" (in our case \"6x%5E2%2B-114x%2B406+=+0\") has the following solutons:
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\n" ); document.write( " \"x%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca\"
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\n" ); document.write( " For these solutions to exist, the discriminant \"b%5E2-4ac\" should not be a negative number.
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\n" ); document.write( " First, we need to compute the discriminant \"b%5E2-4ac\": \"b%5E2-4ac=%28-114%29%5E2-4%2A6%2A406=3252\".
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\n" ); document.write( " Discriminant d=3252 is greater than zero. That means that there are two solutions: \"+x%5B12%5D+=+%28--114%2B-sqrt%28+3252+%29%29%2F2%5Ca\".
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\n" ); document.write( " \"x%5B1%5D+=+%28-%28-114%29%2Bsqrt%28+3252+%29%29%2F2%5C6+=+14.2521924764611\"
\n" ); document.write( " \"x%5B2%5D+=+%28-%28-114%29-sqrt%28+3252+%29%29%2F2%5C6+=+4.74780752353892\"
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\n" ); document.write( " Quadratic expression \"6x%5E2%2B-114x%2B406\" can be factored:
\n" ); document.write( " \"6x%5E2%2B-114x%2B406+=+6%28x-14.2521924764611%29%2A%28x-4.74780752353892%29\"
\n" ); document.write( " Again, the answer is: 14.2521924764611, 4.74780752353892.\n" ); document.write( "Here's your graph:
\n" ); document.write( "\"graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+6%2Ax%5E2%2B-114%2Ax%2B406+%29\"

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