document.write( "Question 1095810: Solve using substitution method
\n" ); document.write( "For 2000 dollars are bought 15 notebooks and 12 markers. How much does 1 notebook and much does 1 marker cost, if 3 markers cost as much as 6 notebooks?
\n" ); document.write( "solving looks something like
\n" ); document.write( "12x+15y=2000
\n" ); document.write( "6y=3x
\n" ); document.write( "Please explain thoroughly and step by step :) \n" ); document.write( "

Algebra.Com's Answer #710305 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let $\"+x+\"$ = the cost of 1 marker
\n" ); document.write( "Let $\"+y+\"$ = the cost of 1 notebook
\n" ); document.write( "----------------------------------
\n" ); document.write( "(1) $\"+12x+%2B+15y+=+2000+\"$
\n" ); document.write( "(2) $\"+3x+=+6y+\"$
\n" ); document.write( "--------------------------------
\n" ); document.write( "Divide both sides of (2) by $\"3+\"$
\n" ); document.write( "(2) $\"+x+=+2y+\"$
\n" ); document.write( "Substitute (2) into (1)
\n" ); document.write( "(1) $\"+12%2A%282y%29+%2B+15y+=+2000+\"$
\n" ); document.write( "(1) $\"+24y+%2B+15y+=+2000+\"$
\n" ); document.write( "(1) $\"+39y+=+2000+\"$
\n" ); document.write( "(1) $\"+y+=+51.28+\"$
\n" ); document.write( "Plug this result back into (2)
\n" ); document.write( "(2) $\"+x+=+2%2A51.28+\"$
\n" ); document.write( "(2) $\"+x+=+102.56+\"$
\n" ); document.write( "----------------------------
\n" ); document.write( "One marker costs 102.56
\n" ); document.write( "One notebook costs 51.28
\n" ); document.write( "----------------------------
\n" ); document.write( "check:
\n" ); document.write( "(1) $\"+12x+%2B+15y+=+2000+\"$
\n" ); document.write( "(1) $\"+12%2A102.56+%2B+15%2A51.28+=+2000+\"$
\n" ); document.write( "(1) $\"+1230.72+%2B+769.2+=+2000+\"$
\n" ); document.write( "(1) $\"+1999.92+\"$
\n" ); document.write( "OK -error due to rounding off
\n" ); document.write( " \n" ); document.write( "

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