document.write( "Question 434087: solve this equation by sustitution
\n" ); document.write( "x=8-4y
\n" ); document.write( "2x-3y=13 \n" ); document.write( "

Algebra.Com's Answer #853256 by ikleyn(53538) $\"\"$ $\"About$

You can put this solution on YOUR website!
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\n" ); document.write( "solve this equation by $\"highlight%28cross%28sustitution%29%29\"$ substitution
\n" ); document.write( "x=8-4y
\n" ); document.write( "2x-3y=13
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\n" ); document.write( "\n" ); document.write( " The way, which @mananth took for the solution in his post, I would compare with a driver,\r
\n" ); document.write( "\n" ); document.write( " who chooses to drive off-road parallel to a highway, instead of driving on the paved highway.\r
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document.write( "In this problem, you are very lucky, because one equation (first one of the two)\r\n" );
document.write( "is just presented in the form ready for substitution.\r\n" );
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document.write( "So, use this (first) equation and replace 'x' in the second equation by 8-4y.\r\n" );
document.write( "You will get then\r\n" );
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document.write( "    2(8-4y) - 3y = 13.\r\n" );
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document.write( "Thus you have single equation for one unknown 'y', and you can easy solve it\r\n" );
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document.write( "    16 - 8y - 3y = 13,\r\n" );
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document.write( "    16 - 11y = 13,\r\n" );
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document.write( "    16 - 13 = 11y,\r\n" );
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document.write( "       3    = 11y,\r\n" );
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document.write( "       y    = .\r\n" );
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document.write( "Having 'y', substitute this value into the first equation and find 'x'\r\n" );
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document.write( "    x = 8 -  = 8 -  =  = .\r\n" );
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document.write( "ANSWER.  x = 76/11;  y = 3/11.\r\n" );
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\n" ); document.write( "\n" ); document.write( "Solved. The EXACT solution is obtained in rational numbers,\r
\n" ); document.write( "\n" ); document.write( "in opposite to the approximate answer in the post by @mananth, expressed in decimals.\r
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\n" ); document.write( "\n" ); document.write( "It is good to use decimals when it is needed.\r
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\n" ); document.write( "\n" ); document.write( "But it is not good using decimals when it is not needed.\r
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\n" ); document.write( "\n" ); document.write( "If to consider the solution by @mananth as a way and a tool for teaching students,
\n" ); document.write( "I would say that this way and this solution are inappropriate.\r
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\n" ); document.write( "\n" ); document.write( "Not because I want to look very smart, but because what I said is a fact.\r
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