document.write( "Question 106125: find two factors of 28 with the sum of 11? \n" ); document.write( "

Algebra.Com's Answer #77230 by alvinjohnburgos(11) $\"\"$ $\"About$

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If we use x and y as variables for the factors:
\n" ); document.write( "eq1 $\"xy+=+28\"$
\n" ); document.write( "eq2 $\"x+%2B+y+=+11\"$
\n" ); document.write( "isolate y in eq2:
\n" ); document.write( " $\"y+=+11+-+x\"$
\n" ); document.write( "Substitute (11-x) for y in eq1:
\n" ); document.write( " $\"%28x%29%2811-x%29+=+28\"$
\n" ); document.write( " $\"11x+-+x%5E2+=+28\"$
\n" ); document.write( " $\"-x%5E2+%2B+11x+-+28+=+0+\"$
\n" ); document.write( " $\"x%5E2+-+11x+%2B+28+=+0+\"$
\n" ); document.write( "Quadratic formula:
\n" ); document.write( " $\"x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"$
\n" ); document.write( " $\"x+=+%2811+%2B-+sqrt%28%28-11%29%5E2+-+4%2A1%2A28%29%29%2F%282%2A1%29\"$
\n" ); document.write( "Simplifying:
\n" ); document.write( " $\"x+=+7+or+4\"$
\n" ); document.write( "Substitute values in eq2:
\n" ); document.write( " $\"7+%2B+y+=+11\"$
\n" ); document.write( " $\"y+=+4\"$
\n" ); document.write( " $\"4+%2B+y+=+11\"$
\n" ); document.write( " $\"y+=+7\"$
\n" ); document.write( "So, the two factors are 7 and 4. \n" ); document.write( "

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