document.write( "Question 168738: 1.
\n" ); document.write( "3x=-5-x
\n" ); document.write( "2x+y=-5\r
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\n" ); document.write( "3x-5y=7
\n" ); document.write( "2x-y=-7\r
\n" ); document.write( "\n" ); document.write( "3.
\n" ); document.write( "x-3y=1
\n" ); document.write( "3x-5y=-5
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Algebra.Com's Answer #124392 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
# 1\r
\n" ); document.write( "\n" ); document.write( "Your first equation has two \"x\" variables. Is there a \"y\" term in the first equation?\r
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\n" ); document.write( "\n" ); document.write( "# 2\r
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\n" ); document.write( "\n" ); document.write( "Start with the given system of equations:\r
\n" ); document.write( "\n" ); document.write( "\"system%283x-5y=7%2C2x-y=-7%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"-5%282x-y%29=-5%28-7%29\" Multiply the both sides of the second equation by -5.\r
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\n" ); document.write( "\n" ); document.write( "\"-10x%2B5y=35\" 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%283x-5y=7%2C-10x%2B5y=35%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( "\"%283x-5y%29%2B%28-10x%2B5y%29=%287%29%2B%2835%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"%283x%2B-10x%29%2B%28-5y%2B5y%29=7%2B35\" Group like terms.\r
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\n" ); document.write( "\n" ); document.write( "\"-7x%2B0y=42\" Combine like terms. Notice how the y terms cancel out.\r
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\n" ); document.write( "\n" ); document.write( "\"-7x=42\" Simplify.\r
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\n" ); document.write( "\n" ); document.write( "\"x=%2842%29%2F%28-7%29\" Divide both sides by \"-7\" to isolate \"x\".\r
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\n" ); document.write( "\n" ); document.write( "\"x=-6\" Reduce.\r
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\n" ); document.write( "\n" ); document.write( "\"3x-5y=7\" Now go back to the first equation.\r
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\n" ); document.write( "\n" ); document.write( "\"3%28-6%29-5y=7\" Plug in \"x=-6\".\r
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\n" ); document.write( "\n" ); document.write( "\"-18-5y=7\" Multiply.\r
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\n" ); document.write( "\n" ); document.write( "\"-5y=7%2B18\" Add \"18\" to both sides.\r
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\n" ); document.write( "\n" ); document.write( "\"-5y=25\" Combine like terms on the right side.\r
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\n" ); document.write( "\n" ); document.write( "\"y=%2825%29%2F%28-5%29\" Divide both sides by \"-5\" to isolate \"y\".\r
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\n" ); document.write( "\n" ); document.write( "\"y=-5\" Reduce.\r
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\n" ); document.write( "\n" ); document.write( "So our answer is \"x=-6\" and \"y=-5\".\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 \"3x-5y=7\" (red) and \"2x-y=-7\" (green) \r
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\n" ); document.write( "\n" ); document.write( "# 3\r
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\n" ); document.write( "\n" ); document.write( "Start with the given system of equations:\r
\n" ); document.write( "\n" ); document.write( "\"system%28x-3y=1%2C3x-5y=-5%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"-3%28x-3y%29=-3%281%29\" Multiply the both sides of the first equation by -3.\r
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\n" ); document.write( "\n" ); document.write( "\"-3x%2B9y=-3\" 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%28-3x%2B9y=-3%2C3x-5y=-5%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( "\"%28-3x%2B9y%29%2B%283x-5y%29=%28-3%29%2B%28-5%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"%28-3x%2B3x%29%2B%289y%2B-5y%29=-3%2B-5\" Group like terms.\r
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\n" ); document.write( "\n" ); document.write( "\"0x%2B4y=-8\" Combine like terms. Notice how the x terms cancel out.\r
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\n" ); document.write( "\n" ); document.write( "\"4y=-8\" Simplify.\r
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\n" ); document.write( "\n" ); document.write( "\"y=%28-8%29%2F%284%29\" Divide both sides by \"4\" 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( "\"-3x%2B9y=-3\" Now go back to the first equation.\r
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\n" ); document.write( "\n" ); document.write( "\"-3x%2B9%28-2%29=-3\" Plug in \"y=-2\".\r
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\n" ); document.write( "\n" ); document.write( "\"-3x-18=-3\" Multiply.\r
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\n" ); document.write( "\n" ); document.write( "\"-3x=-3%2B18\" Add \"18\" to both sides.\r
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\n" ); document.write( "\n" ); document.write( "\"-3x=15\" Combine like terms on the right side.\r
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\n" ); document.write( "\n" ); document.write( "\"x=%2815%29%2F%28-3%29\" Divide both sides by \"-3\" to isolate \"x\".\r
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\n" ); document.write( "\n" ); document.write( "\"x=-5\" Reduce.\r
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\n" ); document.write( "\n" ); document.write( "So our answer is \"x=-5\" 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-3y=1\" (red) and \"3x-5y=-5\" (green) \r
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