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document.write( "Three CD's cost and four DVD's cost $108. Five CD's and three DVD's cost $114. Find the cost of one CD and one DVD. \n" );
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Algebra.Com's Answer #450431 by checkley79(3341) ![]() You can put this solution on YOUR website! 3C+4D=108 MULTIPLY BY 3 \n" ); document.write( "5C+3D=114 MULTIPLY BY -4 & ADD \n" ); document.write( "9C+12D=324 \n" ); document.write( "-20C-12D=-456 \n" ); document.write( "------------------- \n" ); document.write( "-11C=-132 \n" ); document.write( "C=-132/-11 \n" ); document.write( "C=$12 COST OF 1 CD. \n" ); document.write( "3*12+4D=108 \n" ); document.write( "36+4D=108 \n" ); document.write( "4D=108-36 \n" ); document.write( "4D=72 \n" ); document.write( "D=72/4 \n" ); document.write( "D=$18 COST OF 1 DVD. \n" ); document.write( "PROOF: \n" ); document.write( "5*12+3*18=114 \n" ); document.write( "60+54=114 \n" ); document.write( "114=114 \n" ); document.write( " \n" ); document.write( " |