document.write( "Question 607002: Please help I get very confused on these type of math problems. Any help is greatly appreciated.\r
\n" ); document.write( "\n" ); document.write( "(4√5-8√2)(5√5+10√2)= \n" ); document.write( "

Algebra.Com's Answer #382606 by ankor@dixie-net.com(22740) $\"\"$ $\"About$

You can put this solution on YOUR website!
(4√5-8√2)(5√5+10√2)=
\n" ); document.write( ":
\n" ); document.write( "( $\"4sqrt%285%29-8sqrt%282%29\"$ )*( $\"5sqrt%285%29%2B10sqrt%282%29\"$ )
\n" ); document.write( "FOIL
\n" ); document.write( "First: $\"4sqrt%285%29%2A5sqrt%285%29\"$ = 20(5) = 100, we have sqrt(5)*sqrt(5) so it's just 5
\n" ); document.write( ":
\n" ); document.write( "Outer: $\"4sqrt%285%29%2A10sqrt%282%29\"$ = $\"40sqrt%2810%29\"$
\n" ); document.write( ":
\n" ); document.write( "Inner: $\"-8sqrt%282%29%2A5sqrt%285%29\"$ = $\"-40sqrt%2810%29\"$
\n" ); document.write( ":
\n" ); document.write( "Last: $\"-8sqrt%282%29%2A10sqrt%282%29\"$ = -80(2) = -160
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\n" ); document.write( "so we have
\n" ); document.write( "100 + $\"40sqrt%2810%29\"$ - $\"40sqrt%2810%29\"$ - 160
\n" ); document.write( "The middle two terms cancel out, leaving
\n" ); document.write( "100 - 160 = -60
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\n" ); document.write( "Did this un-confuse you somewhat? \n" ); document.write( "

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