document.write( "Question 145832: Solve by the substitution mehtod
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\n" ); document.write( "3x+5y=-11
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Algebra.Com's Answer #106422 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%283x%2B5y=-11%2C-6x%2By=44%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%2B5y=-11\" Start with the first equation\r
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\n" ); document.write( "\n" ); document.write( "\"5y=-11-3x\" Subtract \"3x\" from both sides\r
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\n" ); document.write( "\n" ); document.write( "\"5y=-3x-11\" Rearrange the equation\r
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\n" ); document.write( "\n" ); document.write( "\"y=%28-3x-11%29%2F%285%29\" Divide both sides by \"5\"\r
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\n" ); document.write( "\n" ); document.write( "\"y=%28%28-3%29%2F%285%29%29x%2B%28-11%29%2F%285%29\" Break up the fraction\r
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\n" ); document.write( "\n" ); document.write( "\"y=%28-3%2F5%29x-11%2F5\" Reduce\r
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\n" ); document.write( "\n" ); document.write( "Since \"y=%28-3%2F5%29x-11%2F5\", we can now replace each \"y\" in the second equation with \"%28-3%2F5%29x-11%2F5\" to solve for \"x\"\r
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\n" ); document.write( "\n" ); document.write( "\"-6x%2Bhighlight%28%28%28-3%2F5%29x-11%2F5%29%29=44\" Plug in \"y=%28-3%2F5%29x-11%2F5\" into the first equation. In other words, replace each \"y\" with \"%28-3%2F5%29x-11%2F5\". 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( "\"%285%29%28-6x-%283%2F5%29x-11%2F5%29=%285%29%2844%29\" Multiply both sides by the LCM of 5. This will eliminate the fractions (note: if you need help with finding the LCM, check out this solver)\r
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\n" ); document.write( "\n" ); document.write( "\"-30x-3x-11=220\" Distribute and multiply the LCM to each side\r
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\n" ); document.write( "\n" ); document.write( "\"-33x-11=220\" Combine like terms on the left side\r
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\n" ); document.write( "\n" ); document.write( "\"-33x=220%2B11\"Add 11 to both sides\r
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\n" ); document.write( "\n" ); document.write( "\"-33x=231\" Combine like terms on the right side\r
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\n" ); document.write( "\n" ); document.write( "\"x=%28231%29%2F%28-33%29\" Divide both sides by -33 to isolate x\r
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\n" ); document.write( "\n" ); document.write( "\"x=-7\" 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=-7\"\r
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\n" ); document.write( "\n" ); document.write( "Since we know that \"x=-7\" we can plug it into the equation \"y=%28-3%2F5%29x-11%2F5\" (remember we previously solved for \"y\" in the first equation).\r
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\n" ); document.write( "\n" ); document.write( "\"y=%28-3%2F5%29x-11%2F5\" Start with the equation where \"y\" was previously isolated.\r
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\n" ); document.write( "\n" ); document.write( "\"y=%28-3%2F5%29%28-7%29-11%2F5\" Plug in \"x=-7\"\r
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\n" ); document.write( "\n" ); document.write( "\"y=21%2F5-11%2F5\" Multiply\r
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\n" ); document.write( "\n" ); document.write( "\"y=2\" Combine like terms and reduce. (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=2\"\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( "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%2B5y=-11\" (red) and \"-6x%2By=44\" (green) and the intersection of the lines (blue circle).\r
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