document.write( "Question 612882: Solve using the substitution method:
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document.write( "x-y=5
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document.write( "x+2y=7
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document.write( "and please explain...thank you \n" );
document.write( "
Algebra.Com's Answer #385761 by jim_thompson5910(35256)![]() ![]() ![]() You can put this solution on YOUR website! Isolate x in the first equation x-y=5 to get\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x-y=5\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x=5+y\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now plug this into the second equation\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x+2y = 7\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "5+y+2y = 7 ... replace 'x' with 5+y (since x=5+y)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "*** Notice how this completely gets rid of 'x' in the second equation. This leaves us with y.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now solve for y\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "5+y+2y = 7\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "5+3y = 7\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "3y = 7-5\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "3y = 2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "y = 2/3\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now that we know that y = 2/3, we can use this to find x.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x = 5+y\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x = 5+2/3\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x = 15/3+2/3\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x = 17/3\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "So the solutions are x = 17/3 and y = 2/3\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "These solutions can be represented as the ordered pair (17/3, 2/3) \n" ); document.write( " |