document.write( "Question 395356: Solve using the substitutiion method\r
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Algebra.Com's Answer #280574 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
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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%28-3x%2By=4%2Cx%2B3y=22%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( "\"-3x%2By=4\" Start with the first equation\r
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\n" ); document.write( "\n" ); document.write( "\"y=4%2B3x\" Add \"3x\" to both sides\r
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\n" ); document.write( "\n" ); document.write( "\"y=%2B3x%2B4\" Rearrange the equation\r
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\n" ); document.write( "\n" ); document.write( "\"y=%28%2B3x%2B4%29%2F%281%29\" Divide both sides by \"1\"\r
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\n" ); document.write( "\n" ); document.write( "\"y=%28%28%2B3%29%2F%281%29%29x%2B%284%29%2F%281%29\" Break up the fraction\r
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\n" ); document.write( "\n" ); document.write( "\"y=3x%2B4\" Reduce\r
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\n" ); document.write( "\n" ); document.write( "Since \"y=3x%2B4\", we can now replace each \"y\" in the second equation with \"3x%2B4\" to solve for \"x\"\r
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\n" ); document.write( "\n" ); document.write( "\"x%2B3highlight%28%283x%2B4%29%29=22\" Plug in \"y=3x%2B4\" into the second equation. In other words, replace each \"y\" with \"3x%2B4\". 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%2B%283%29%283%29x%2B%283%29%284%29=22\" Distribute \"3\" to \"3x%2B4\"\r
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\n" ); document.write( "\n" ); document.write( "\"x%2B9x%2B12=22\" Multiply\r
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\n" ); document.write( "\n" ); document.write( "\"10x%2B12=22\" Combine like terms on the left side\r
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\n" ); document.write( "\n" ); document.write( "\"10x=22-12\"Subtract 12 from both sides\r
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\n" ); document.write( "\n" ); document.write( "\"10x=10\" Combine like terms on the right side\r
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\n" ); document.write( "\n" ); document.write( "\"x=%2810%29%2F%2810%29\" Divide both sides by 10 to isolate x\r
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\n" ); document.write( "\n" ); document.write( "\"x=1\" 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=1\"\r
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\n" ); document.write( "\n" ); document.write( "Since we know that \"x=1\" we can plug it into the equation \"y=3x%2B4\" (remember we previously solved for \"y\" in the first equation).\r
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\n" ); document.write( "\n" ); document.write( "\"y=3x%2B4\" Start with the equation where \"y\" was previously isolated.\r
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\n" ); document.write( "\n" ); document.write( "\"y=3%281%29%2B4\" Plug in \"x=1\"\r
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\n" ); document.write( "\n" ); document.write( "\"y=3%2B4\" Multiply\r
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\n" ); document.write( "\n" ); document.write( "\"y=7\" 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=7\"\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=1\" and \"y=7\"\r
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\n" ); document.write( "\n" ); document.write( "which form the point \r
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\n" ); document.write( "\n" ); document.write( "Now let's graph the two equations (if you need help with graphing, check out this solver)\r
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\n" ); document.write( "\n" ); document.write( "From the graph, we can see that the two equations intersect at . This visually verifies our answer.\r
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\n" ); document.write( "\n" ); document.write( " graph of \"-3x%2By=4\" (red) and \"x%2B3y=22\" (green) and the intersection of the lines (blue circle).\r
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\n" ); document.write( "\n" ); document.write( "If you need more help, email me at jim_thompson5910@hotmail.com\r
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\n" ); document.write( "\n" ); document.write( "Also, feel free to check out my tutoring website\r
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\n" ); document.write( "\n" ); document.write( "Jim
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