document.write( "Question 1016156: The sum of a number and 8, mulitipled by the sum of the number and 5 is equivalent to 19. \n" ); document.write( "
Algebra.Com's Answer #632555 by macston(5194)\"\" \"About 
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\n" ); document.write( "You did not ask a question.
\n" ); document.write( "Assuming you want to find the number.
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\n" ); document.write( "x=the number
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\n" ); document.write( "(x+8)(x+5)=19
\n" ); document.write( "x^2+13x+40=19
\n" ); document.write( "x^2+13x+21=0
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Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation \"ax%5E2%2Bbx%2Bc=0\" (in our case \"1x%5E2%2B13x%2B21+=+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=%2813%29%5E2-4%2A1%2A21=85\".
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\n" ); document.write( " Discriminant d=85 is greater than zero. That means that there are two solutions: \"+x%5B12%5D+=+%28-13%2B-sqrt%28+85+%29%29%2F2%5Ca\".
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\n" ); document.write( " \"x%5B1%5D+=+%28-%2813%29%2Bsqrt%28+85+%29%29%2F2%5C1+=+-1.89022777135356\"
\n" ); document.write( " \"x%5B2%5D+=+%28-%2813%29-sqrt%28+85+%29%29%2F2%5C1+=+-11.1097722286464\"
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\n" ); document.write( " Quadratic expression \"1x%5E2%2B13x%2B21\" can be factored:
\n" ); document.write( " \"1x%5E2%2B13x%2B21+=+1%28x--1.89022777135356%29%2A%28x--11.1097722286464%29\"
\n" ); document.write( " Again, the answer is: -1.89022777135356, -11.1097722286464.\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%2B13%2Ax%2B21+%29\"

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\n" ); document.write( "ANSWER: The number is -1.89 or -11.11.
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\n" ); document.write( "CHECK:
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\n" ); document.write( "For x=-1.89
\n" ); document.write( "(x+8)(x+5)=19
\n" ); document.write( "(-1.89+8)(-1.89+5)=19
\n" ); document.write( "(6.11)(3.11)=19
\n" ); document.write( "19=19
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\n" ); document.write( "For -11.11
\n" ); document.write( "(-11.11+8)(-11.11+5)=19
\n" ); document.write( "(-3.11)(-6.11)=19
\n" ); document.write( "19=19
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