document.write( "Question 447108: find 3n^2 if n(n+5)=-4 \n" ); document.write( "
Algebra.Com's Answer #307855 by chriswen(106)\"\" \"About 
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n(n+5)=-4
\n" ); document.write( "n^2+5n=-4
\n" ); document.write( "n^2+5n+4=0
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Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation \"an%5E2%2Bbn%2Bc=0\" (in our case \"1n%5E2%2B5n%2B4+=+0\") has the following solutons:
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\n" ); document.write( " \"n%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=%285%29%5E2-4%2A1%2A4=9\".
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\n" ); document.write( " Discriminant d=9 is greater than zero. That means that there are two solutions: \"+x%5B12%5D+=+%28-5%2B-sqrt%28+9+%29%29%2F2%5Ca\".
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\n" ); document.write( " \"n%5B1%5D+=+%28-%285%29%2Bsqrt%28+9+%29%29%2F2%5C1+=+-1\"
\n" ); document.write( " \"n%5B2%5D+=+%28-%285%29-sqrt%28+9+%29%29%2F2%5C1+=+-4\"
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\n" ); document.write( " Quadratic expression \"1n%5E2%2B5n%2B4\" can be factored:
\n" ); document.write( " \"1n%5E2%2B5n%2B4+=+1%28n--1%29%2A%28n--4%29\"
\n" ); document.write( " Again, the answer is: -1, -4.\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%2B5%2Ax%2B4+%29\"

\n" ); document.write( "\n" ); document.write( "Therefore n = -1 or -4.
\n" ); document.write( "3n^2= 3 or 48
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