document.write( "Question 293167: Last month a man paid $65 for 5 dvds and 2 cd's. This month he paid $81 for 3 dvd's and 4 cd's. How much were the DVD's and CD's? \n" ); document.write( "

Algebra.Com's Answer #211603 by mananth(16949) $\"\"$ $\"About$

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let the dvd cost x\r
\n" ); document.write( "\n" ); document.write( "let the cd cost y\r
\n" ); document.write( "\n" ); document.write( "last month\r
\n" ); document.write( "\n" ); document.write( "5x+2y=65\r
\n" ); document.write( "\n" ); document.write( "this month\r
\n" ); document.write( "\n" ); document.write( "3x+4y =81\r
\n" ); document.write( "\n" ); document.write( "3(5x+2y)= 3*65\r
\n" ); document.write( "\n" ); document.write( "5(3x+4y)=5*81\r
\n" ); document.write( "\n" ); document.write( "18x+6y = 195\r
\n" ); document.write( "\n" ); document.write( "18x+20y=405\r
\n" ); document.write( "\n" ); document.write( "subtract the equations\r
\n" ); document.write( "\n" ); document.write( "-14y=- 210\r
\n" ); document.write( "\n" ); document.write( "y=-210/-14\r
\n" ); document.write( "\n" ); document.write( "y=15\r
\n" ); document.write( "\n" ); document.write( "By substituting the value of y in any equation we get x=7\r
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\n" ); document.write( "\n" ); document.write( "x=7\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

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