document.write( "Question 166627: I don't understand this method of solving? could you show me both parts of this problem in the long form for my reference.\r
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\n" ); document.write( "\n" ); document.write( " 4x+9y = 395
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\n" ); document.write( "\n" ); document.write( "Using Substitution Method.\r
\n" ); document.write( "\n" ); document.write( "Expressing x as a function of y (from the first equation) x = (395 -9y)/4\r
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\n" ); document.write( "\n" ); document.write( " 1(395+9y)/4+y = 80\r
\n" ); document.write( "\n" ); document.write( "Simplifying this expression:\r
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Algebra.Com's Answer #122801 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
Note: I'm going to make the first equation \"x%2By+=+80\" and the second equation \"4x%2B9y=395\" (it is valid to relabel the equations)\r
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\n" ); document.write( "\n" ); document.write( "Start with the given system of equations:\r
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\n" ); document.write( "\n" ); document.write( "\"system%28x%2By=80%2C4x%2B9y=395%29\"\r
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\n" ); document.write( "\n" ); document.write( "Now in order to solve this system by using substitution, we need to solve (or isolate) one variable. I'm going to solve for y.\r
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\n" ); document.write( "\n" ); document.write( "So let's isolate y in the first equation\r
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\n" ); document.write( "\n" ); document.write( "\"x%2By=80\" Start with the first equation\r
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\n" ); document.write( "\n" ); document.write( "\"y=80-x\" Subtract \"x\" from both sides\r
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\n" ); document.write( "\n" ); document.write( "\"y=-x%2B80\" Rearrange the equation\r
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\n" ); document.write( "\n" ); document.write( "Since \"y=-x%2B80\", we can now replace each \"y\" in the second equation with \"-x%2B80\" to solve for \"x\"\r
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\n" ); document.write( "\n" ); document.write( "\"4x%2B9highlight%28%28-x%2B80%29%29=395\" Plug in \"y=-x%2B80\" into the second equation. In other words, replace each \"y\" with \"-x%2B80\". 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( "\"4x%2B%289%29%28-1%29x%2B%289%29%2880%29=395\" Distribute \"9\" to \"-x%2B80\"\r
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\n" ); document.write( "\n" ); document.write( "\"4x-9x%2B720=395\" Multiply\r
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\n" ); document.write( "\n" ); document.write( "\"-5x%2B720=395\" Combine like terms on the left side\r
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\n" ); document.write( "\n" ); document.write( "\"-5x=395-720\"Subtract 720 from both sides\r
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\n" ); document.write( "\n" ); document.write( "\"-5x=-325\" Combine like terms on the right side\r
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\n" ); document.write( "\n" ); document.write( "\"x=%28-325%29%2F%28-5%29\" Divide both sides by -5 to isolate x\r
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\n" ); document.write( "\n" ); document.write( "\"x=65\" Divide\r
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\n" ); document.write( "\n" ); document.write( "-----------------First Answer------------------------------\r
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\n" ); document.write( "\n" ); document.write( "So the first part of our answer is: \"x=65\"\r
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\n" ); document.write( "\n" ); document.write( "Since we know that \"x=65\" we can plug it into the equation \"y=-x%2B80\" (remember we previously solved for \"y\" in the first equation).\r
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\n" ); document.write( "\n" ); document.write( "\"y=-x%2B80\" Start with the equation where \"y\" was previously isolated.\r
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\n" ); document.write( "\n" ); document.write( "\"y=-%2865%29%2B80\" Plug in \"x=65\"\r
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\n" ); document.write( "\n" ); document.write( "\"y=-65%2B80\" Multiply\r
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\n" ); document.write( "\n" ); document.write( "\"y=15\" Combine like terms \r
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\n" ); document.write( "\n" ); document.write( "-----------------Second Answer------------------------------\r
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\n" ); document.write( "\n" ); document.write( "So the second part of our answer is: \"y=15\"\r
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\n" ); document.write( "\n" ); document.write( "-----------------Summary------------------------------\r
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\n" ); document.write( "\n" ); document.write( "So our answers are:\r
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\n" ); document.write( "\n" ); document.write( "\"x=65\" and \"y=15\"\r
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\n" ); document.write( "\n" ); document.write( "which form the ordered pair \r
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