document.write( "Question 1156399: If the length of a rectangle is 7 meters less than twice the width, we have
\n" ); document.write( "L=2W-7
\n" ); document.write( "If the area is 60 square meters, we have
\n" ); document.write( "L×W=60 substitute L
\n" ); document.write( "(2W-7)×W=60
\n" ); document.write( "2W^2-7W=60
\n" ); document.write( "2W^2-7W-60=0
\n" ); document.write( "2W^2-15W+8W-60=0
\n" ); document.write( "(2W^2+8W)-(15W-60)=0
\n" ); document.write( "2W(W+4)-15(W+4)=0
\n" ); document.write( "(W+4)(2W-15)=0
\n" ); document.write( "2W-15=0 W=15/2 W=7.5
\n" ); document.write( "Can someone explain where the 15 and 8 came from? \n" ); document.write( "

Algebra.Com's Answer #779123 by MathTherapy(10552) $\"\"$ $\"About$

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\n" ); document.write( " If the length of a rectangle is 7 meters less than twice the width, we have
\n" ); document.write( "L=2W-7
\n" ); document.write( "If the area is 60 square meters, we have
\n" ); document.write( "L×W=60 substitute L
\n" ); document.write( "(2W-7)×W=60
\n" ); document.write( "2W^2-7W=60
\n" ); document.write( "2W^2-7W-60=0
\n" ); document.write( "2W^2-15W+8W-60=0
\n" ); document.write( "(2W^2+8W)-(15W-60)=0
\n" ); document.write( "2W(W+4)-15(W+4)=0
\n" ); document.write( "(W+4)(2W-15)=0
\n" ); document.write( "2W-15=0 W=15/2 W=7.5
\n" ); document.write( "Can someone explain where the 15 and 8 came from?
\n" ); document.write( "

 
\n" );
document.write( "  <===== I guess you're referring to the - 15 and + 8 here
\n" );
document.write( "The - 15W + 8W REPLACES - 7W since - 15W + 8W = - 7W
\n" );
document.write( "The - 15 and + 8 were derived from the NEED to find 2 factors with a product of \"ac,\" or + 2 * - 60 = - 120, and simultaneously SUM to - 7. 
\n" );
document.write( "These 2 factors are: - 15 and + 8 (notice that the factors have OPPOSITE signs!). \n" );
document.write( "

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