document.write( "Question 146212: Solve by substitution method \r
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Algebra.Com's Answer #106791 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
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\n" ); document.write( "\n" ); document.write( "\"system%283x%2By=2%2C-x-3y=6%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( "\"-x-3highlight%28%28-3x%2B2%29%29=6\" Plug in \"y=-3x%2B2\" into the first 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%2B%28-3%29%28-3%29x%2B%28-3%29%282%29=6\" Distribute \"-3\" to \"-3x%2B2\"\r
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\n" ); document.write( "\n" ); document.write( "\"-x%2B9x-6=6\" Multiply\r
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\n" ); document.write( "\n" ); document.write( "\"8x-6=6\" Combine like terms on the left side\r
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\n" ); document.write( "\n" ); document.write( "\"8x=6%2B6\"Add 6 to both sides\r
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\n" ); document.write( "\n" ); document.write( "\"8x=12\" Combine like terms on the right side\r
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\n" ); document.write( "\n" ); document.write( "\"x=%2812%29%2F%288%29\" Divide both sides by 8 to isolate x\r
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\n" ); document.write( "\n" ); document.write( "\"x=3%2F2\" Reduce\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=3%2F2\"\r
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\n" ); document.write( "\n" ); document.write( "Since we know that \"x=3%2F2\" 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%283%2F2%29%2B2\" Plug in \"x=3%2F2\"\r
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\n" ); document.write( "\n" ); document.write( "\"y=-9%2F2%2B2\" Multiply\r
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\n" ); document.write( "\n" ); document.write( "\"y=-5%2F2\" Combine like terms (note: if you need help with fractions, check out this solver)\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=-5%2F2\"\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=3%2F2\" and \"y=-5%2F2\"\r
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\n" ); document.write( "\n" ); document.write( "which form the ordered pair: \r
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