document.write( "Question 147493: -9=x-3y\r
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Algebra.Com's Answer #107866 by jim_thompson5910(35256)\"\" \"About 
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\n" ); document.write( "\"-9=x-3y\" Start with the first equation.\r
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\n" ); document.write( "\n" ); document.write( "\"0=x-3y%2B9\" Add \"9\" to both sides.\r
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\n" ); document.write( "\n" ); document.write( "\"-x=-3y%2B9\" Subtract \"x\" from both sides.\r
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\n" ); document.write( "\n" ); document.write( "\"-x%2B3y=9\" Add \"3y\" to both sides.\r
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\n" ); document.write( "\n" ); document.write( "\"-2x%2B6=6y\" Start with the second equation.\r
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\n" ); document.write( "\n" ); document.write( "\"-2x=6y-6\" Subtract \"6\" from both sides.\r
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\n" ); document.write( "\n" ); document.write( "\"-2x-6y=-6\" Subtract \"6y\" from both sides.\r
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\n" ); document.write( "\n" ); document.write( "So we have the system of equations:\r
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\n" ); document.write( "\n" ); document.write( "\"system%28-x%2B3y=9%2C-2x-6y=-6%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"2%28-x%2B3y%29=2%289%29\" Multiply the both sides of the first equation by 2.\r
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\n" ); document.write( "\n" ); document.write( "\"-2x%2B6y=18\" Distribute and multiply.\r
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\n" ); document.write( "\n" ); document.write( "\"-1%28-2x-6y%29=-1%28-6%29\" Multiply the both sides of the second equation by -1.\r
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\n" ); document.write( "\n" ); document.write( "\"2x%2B6y=6\" Distribute and multiply.\r
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\n" ); document.write( "\n" ); document.write( "So we have the new system of equations:\r
\n" ); document.write( "\n" ); document.write( "\"system%28-2x%2B6y=18%2C2x%2B6y=6%29\"\r
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\n" ); document.write( "\n" ); document.write( "Now add the equations together. You can do this by simply adding the two left sides and the two right sides separately like this:\r
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\n" ); document.write( "\n" ); document.write( "\"%28-2x%2B6y%29%2B%282x%2B6y%29=%2818%29%2B%286%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"%28-2x%2B2x%29%2B%286y%2B6y%29=18%2B6\" Group like terms.\r
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\n" ); document.write( "\n" ); document.write( "\"0x%2B12y=24\" Combine like terms. Notice how the x terms cancel out.\r
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\n" ); document.write( "\n" ); document.write( "\"12y=24\" Simplify.\r
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\n" ); document.write( "\n" ); document.write( "\"y=%2824%29%2F%2812%29\" Divide both sides by \"12\" to isolate \"y\".\r
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\n" ); document.write( "\n" ); document.write( "\"y=2\" Reduce.\r
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\n" ); document.write( "\n" ); document.write( "\"-2x%2B6y=18\" Now go back to the first equation.\r
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\n" ); document.write( "\n" ); document.write( "\"-2x%2B6%282%29=18\" Plug in \"y=2\".\r
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\n" ); document.write( "\n" ); document.write( "\"-2x%2B12=18\" Multiply.\r
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\n" ); document.write( "\n" ); document.write( "\"-2x=18-12\" Subtract \"12\" from both sides.\r
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\n" ); document.write( "\n" ); document.write( "\"-2x=6\" Combine like terms on the right side.\r
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\n" ); document.write( "\n" ); document.write( "\"x=%286%29%2F%28-2%29\" Divide both sides by \"-2\" to isolate \"x\".\r
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\n" ); document.write( "\n" ); document.write( "\"x=-3\" Reduce.\r
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\n" ); document.write( "\n" ); document.write( "So our answer is \"x=-3\" and \"y=2\".\r
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\n" ); document.write( "\n" ); document.write( "Which form the ordered pair .\r
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\n" ); document.write( "\n" ); document.write( "This means that the system is consistent and independent.\r
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\n" ); document.write( "\n" ); document.write( "Notice when we graph the equations, we see that they intersect at . So this visually verifies our answer.\r
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\n" ); document.write( "\n" ); document.write( " Graph of \"-x%2B3y=9\" (red) and \"-2x-6y=-6\" (green) \r
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