document.write( "Question 120687: please help me solve this promblem
\n" ); document.write( "use the substitution method to solve the linear system
\n" ); document.write( "here is the promblem
\n" ); document.write( "x-5y=-10
\n" ); document.write( "y=-2x-9
\n" ); document.write( "please help
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Algebra.Com's Answer #88467 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
Start with the given system\r
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\n" ); document.write( "\"y=-2x-9\"\r
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\n" ); document.write( "\n" ); document.write( "\"x-5%28-2x-9%29=-10\" Plug in \"y=-2x-9\" into the first equation. In other words, replace each \"y\" with \"-2x-9\". Notice we've eliminated the \"y\" variables. So we now have a simple equation with one unknown.\r
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\n" ); document.write( "\n" ); document.write( "\"x%2B10x%2B45=-10\" Distribute\r
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\n" ); document.write( "\n" ); document.write( "\"11x%2B45=-10\" Combine like terms on the left side\r
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\n" ); document.write( "\n" ); document.write( "\"11x=-10-45\"Subtract 45 from both sides\r
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\n" ); document.write( "\n" ); document.write( "\"11x=-55\" Combine like terms on the right side\r
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\n" ); document.write( "\n" ); document.write( "\"x=%28-55%29%2F%2811%29\" Divide both sides by 11 to isolate x\r
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\n" ); document.write( "\n" ); document.write( "\"x=-5\" Divide\r
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\n" ); document.write( "\n" ); document.write( "Now that we know that \"x=-5\", we can plug this into \"y=-2x-9\" to find \"y\"\r
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\n" ); document.write( "\n" ); document.write( "\"y=-2%28-5%29-9\" Substitute \"-5\" for each \"x\"\r
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\n" ); document.write( "\n" ); document.write( "\"y=1\" Simplify\r
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\n" ); document.write( "\n" ); document.write( "So our answer is \"x=-5\" and \"y=1\" which also looks like \r
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\n" ); document.write( "\n" ); document.write( "Notice if we graph the two equations, we can see that their intersection is at . So this verifies our answer.\r
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\n" ); document.write( "\n" ); document.write( "\"+graph%28+500%2C+500%2C+-7%2C+7%2C+-7%2C+7%2C+%28-10-x%29%2F-5%2C+-2x-9%29+\" Graph of \"x-5y=-10\" (red) and \"y=-2x-9\" (green)\r
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