document.write( "Question 667139: I am trying to solve an equation by factoring. The equation is:\r
\n" ); document.write( "\n" ); document.write( "x^2/2 + x/20 = 10\r
\n" ); document.write( "\n" ); document.write( "What I have done is cleared the denominators and ended up with:\r
\n" ); document.write( "\n" ); document.write( "10x^2 + x = 10\r
\n" ); document.write( "\n" ); document.write( "Then I moved the 10 to the left side of the equation and ended up with:\r
\n" ); document.write( "\n" ); document.write( "10x^2 + x -10 = 0\r
\n" ); document.write( "\n" ); document.write( "I am stuck and cannot factor: 10x^2 + x -10\r
\n" ); document.write( "\n" ); document.write( "The answer in the back of the book is: {2/5, -1/2}, but am not sure how to get to this answer without successfully factoring first.\r
\n" ); document.write( "\n" ); document.write( "In an attempt to factor, I multiplied the first and last coefficients and came up with -100. There are no numbers that when multiplied together equal -100 and also equal the middle coefficient of 1 when added together.\r
\n" ); document.write( "\n" ); document.write( "Please help.
\n" ); document.write( "

Algebra.Com's Answer #414816 by josmiceli(19441)\"\" \"About 
You can put this solution on YOUR website!
\"+%28x%5E2%29%2F2+%2B+x%2F20+=+10+\"
\n" ); document.write( "You are not simply changing the appearance
\n" ); document.write( "of the fractions on the left side. This would be
\n" ); document.write( "the case if you did:
\n" ); document.write( "\"+%2810%2F10%29%2A%28%28x%5E2%29%2F2%29+%2B+x%2F20+=+10+\"
\n" ); document.write( "Note that you haven't really changed the value
\n" ); document.write( "of the left side
\n" ); document.write( "\"+%28+10x%5E2+%29%2F+20+%2B+x%2F20+=+200%2F20+\"
\n" ); document.write( "Now you can multiply through by \"+20+\"
\n" ); document.write( "\"+10x%5E2+%2B+x+=+200+\"
\n" ); document.write( "--------------------------
\n" ); document.write( "What you wanted to do was multiply both sides by \"+20+\"
\n" ); document.write( "\"+%28x%5E2%29%2F2+%2B+x%2F20+=+10+\"
\n" ); document.write( "\"+10x%5E2+%2B+x+=+200+\"
\n" ); document.write( "same answer
\n" ); document.write( "\"+10x%5E2+%2B+x+-+200+=+0+\"
\n" ); document.write( "You can use the 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( "\"+a+=+10+\"
\n" ); document.write( "\"+b+=+1+\"
\n" ); document.write( "\"+c+=+-200+\"
\n" ); document.write( "\"+x+=+%28-1+%2B-+sqrt%28+1%5E2+-+4%2A10%2A%28-200%29+%29%29+%2F+%282%2A10%29+\"
\n" ); document.write( "\"+x+=+%28-1+%2B-+sqrt%28+1+%2B+8000+%29%29+%2F+20+\"
\n" ); document.write( "\"+x+=+%28-1+%2B-+sqrt%28+8001+%29%29+%2F+20+\"
\n" ); document.write( "\"+x+=+%28+-1+%2B+89.4483+%29+%2F+20+\"
\n" ); document.write( "\"+x+=+88.4483+%2F+20+\"
\n" ); document.write( "\"+x+=+4.4224+\"
\n" ); document.write( "and
\n" ); document.write( "\"+x+=+%28+-1+-+89.4483+%29+%2F+20+\"
\n" ); document.write( "\"+x+=+%28+-90.4483+%29+%2F+20+\"
\n" ); document.write( "\"+x+=+-4.5224+\"
\n" ); document.write( "check:
\n" ); document.write( "\"+%28+x+-+4.4224+%29%2A%28+x+%2B+4.5224+%29+\"
\n" ); document.write( "\"+x%5E2+%2B+.1x+-+20+\"
\n" ); document.write( "Multiply both sides by \"+1%2F2+\"
\n" ); document.write( "\"+%28x%5E2%29%2F2+%2B+x%2F20+-+10+=+0+\"
\n" ); document.write( "\"+%28x%5E2%29%2F2+%2B+x%2F20+=+10+\"
\n" ); document.write( "OK
\n" ); document.write( "Why does the book disagree? I don't know
\n" ); document.write( "
\n" ); document.write( "
\n" );