document.write( "Question 854758: What multiplies to give you -60 and adds to give you -1 \n" ); document.write( "
Algebra.Com's Answer #514886 by Seutip(231)\"\" \"About 
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Let a - be one of the number
\n" ); document.write( " b - be the second number\r
\n" ); document.write( "\n" ); document.write( "When given a question of this nature, you can look upon the two numbers as the factors in two polynomials that give you a quadratic when multiplied. That sounds complicated, but I mean this: \r
\n" ); document.write( "\n" ); document.write( "\"%28x+%2B+a%29%28x+%2B+b%29+\"\r
\n" ); document.write( "\n" ); document.write( "Use our friend Mr. Foil\r
\n" ); document.write( "\n" ); document.write( "\"x%5E2+%2B+%28a+%2B+b%29x+%2B+ab+\"\r
\n" ); document.write( "\n" ); document.write( "So they give you a product of \"ab\" and a sum of \"a + b\". You are looking for exactly that, two numbers that multiply to give a product you specify and add to give the sum you specify. \r
\n" ); document.write( "\n" ); document.write( "If you substitute the sum, -1, and the product, -60, you get: \r
\n" ); document.write( "\n" ); document.write( "\"x%5E2%2B%28-1%29x%2B%28-60%29-0\"
\n" ); document.write( "\"x%5E2-x-60=0\" Since it's not a perfect trinomial we use completing the square
\n" ); document.write( "\"x%5E2-x%2B1%2F4=60%2B1%2F4\" It's 1/4 because 3rd term = ((-1)/2)^2
\n" ); document.write( "\"sqrt%28x-1%2F2%29%5E2=sqrt%2860%2A1%2F4%29\"
\n" ); document.write( "\"x-1%2F2=sqrt15\"
\n" ); document.write( "\"x=sqrt15%2B1%2F2\"\r
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\n" ); document.write( "\n" ); document.write( "Hope that helps!\r
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