document.write( "Question 330594: Suppose the width of a rectangle is 5cm less than half its length. Its area is 72 cm squared. What is the length and width of the rectangle? \n" ); document.write( "
Algebra.Com's Answer #236993 by JBarnum(2146)\"\" \"About 
You can put this solution on YOUR website!
a=lw know your formulas
\n" ); document.write( "a=72
\n" ); document.write( "w=(l/2)-5
\n" ); document.write( "\"72=l%28%28l%2F2%29-5%29\"
\n" ); document.write( "\"72=%28l%5E2%2F2%29-5l\"
\n" ); document.write( "\"144=l%5E2-10l\"
\n" ); document.write( "\"0=l%5E2-10l-144\" view below for quadratic explaination
\n" ); document.write( "\"l=18\"
\n" ); document.write( "72/18=w
\n" ); document.write( "\"w=4\"
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Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation \"al%5E2%2Bbl%2Bc=0\" (in our case \"1l%5E2%2B-10l%2B-144+=+0\") has the following solutons:
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\n" ); document.write( " \"l%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=%28-10%29%5E2-4%2A1%2A-144=676\".
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\n" ); document.write( " Discriminant d=676 is greater than zero. That means that there are two solutions: \"+x%5B12%5D+=+%28--10%2B-sqrt%28+676+%29%29%2F2%5Ca\".
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\n" ); document.write( " \"l%5B1%5D+=+%28-%28-10%29%2Bsqrt%28+676+%29%29%2F2%5C1+=+18\"
\n" ); document.write( " \"l%5B2%5D+=+%28-%28-10%29-sqrt%28+676+%29%29%2F2%5C1+=+-8\"
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\n" ); document.write( " Quadratic expression \"1l%5E2%2B-10l%2B-144\" can be factored:
\n" ); document.write( " \"1l%5E2%2B-10l%2B-144+=+1%28l-18%29%2A%28l--8%29\"
\n" ); document.write( " Again, the answer is: 18, -8.\n" ); document.write( "Here's your graph:
\n" ); document.write( "\"graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+1%2Ax%5E2%2B-10%2Ax%2B-144+%29\"

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