document.write( "Question 395438: How to solve 3x+y=2 with substatution of 4x+y=20???? \n" ); document.write( "
Algebra.Com's Answer #280629 by jim_thompson5910(35256)\"\" \"About 
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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%283x%2By=2%2C4x%2By=20%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=2\" Start with the first equation\r
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\n" ); document.write( "\n" ); document.write( "\"y=2-3x\" Subtract \"3x\" from both sides\r
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\n" ); document.write( "\n" ); document.write( "\"y=-3x%2B2\" Rearrange the equation\r
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\n" ); document.write( "\n" ); document.write( "Since \"y=-3x%2B2\", we can now replace each \"y\" in the second equation with \"-3x%2B2\" to solve for \"x\"\r
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\n" ); document.write( "\n" ); document.write( "\"4x%2Bhighlight%28%28-3x%2B2%29%29=20\" Plug in \"y=-3x%2B2\" into the second equation. In other words, replace each \"y\" with \"-3x%2B2\". 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%2B2=20\" Combine like terms on the left side\r
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\n" ); document.write( "\n" ); document.write( "\"x=20-2\"Subtract 2 from both sides\r
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\n" ); document.write( "\n" ); document.write( "\"x=18\" Combine like terms on the right side\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=18\"\r
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\n" ); document.write( "\n" ); document.write( "Since we know that \"x=18\" we can plug it into the equation \"y=-3x%2B2\" (remember we previously solved for \"y\" in the first equation).\r
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\n" ); document.write( "\n" ); document.write( "\"y=-3x%2B2\" Start with the equation where \"y\" was previously isolated.\r
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\n" ); document.write( "\n" ); document.write( "\"y=-3%2818%29%2B2\" Plug in \"x=18\"\r
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\n" ); document.write( "\n" ); document.write( "\"y=-54%2B2\" Multiply\r
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\n" ); document.write( "\n" ); document.write( "\"y=-52\" 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=-52\"\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=18\" and \"y=-52\"\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( "So the system is both consistent and independent.\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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