document.write( "Question 130331: My study question asks....Solve the following systems of equation by any method. \r
\n" ); document.write( "\n" ); document.write( "All I am asking for is the name of a method so I can look up the order or way to solve it. \r
\n" ); document.write( "\n" ); document.write( "3x-2y=12\r
\n" ); document.write( "\n" ); document.write( "and\r
\n" ); document.write( "\n" ); document.write( "2x+y=8\r
\n" ); document.write( "\n" ); document.write( "Thanks!
\n" ); document.write( "

Algebra.Com's Answer #95195 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
You can solve this by substitution, elimination, or graphing\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Let's solve this system by substitution\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Start with the given system of equations:\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"system%283x-2y=12%2C2x%2By=8%29\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\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
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "So let's isolate y in the first equation\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"3x-2y=12\" Start with the first equation\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"-2y=12-3x\" Subtract \"3x\" from both sides\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"-2y=-3x%2B12\" Rearrange the equation\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y=%28-3x%2B12%29%2F%28-2%29\" Divide both sides by \"-2\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y=%28%28-3%29%2F%28-2%29%29x%2B%2812%29%2F%28-2%29\" Break up the fraction\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y=%283%2F2%29x-6\" Reduce\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "---------------------\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Since \"y=%283%2F2%29x-6\", we can now replace each \"y\" in the second equation with \"%283%2F2%29x-6\" to solve for \"x\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"2x%2Bhighlight%28%28%283%2F2%29x-6%29%29=8\" Plug in \"y=%283%2F2%29x-6\" into the first equation. In other words, replace each \"y\" with \"%283%2F2%29x-6\". Notice we've eliminated the \"y\" variables. So we now have a simple equation with one unknown.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"%282%29%282x%2B%283%2F2%29x-6%29=%282%29%288%29\" Multiply both sides by the LCM of 2. This will eliminate the fractions (note: if you need help with finding the LCM, check out this solver)\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"4x%2B3x-12=16\" Distribute and multiply the LCM to each side\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"7x-12=16\" Combine like terms on the left side\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"7x=16%2B12\"Add 12 to both sides\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"7x=28\" Combine like terms on the right side\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x=%2828%29%2F%287%29\" Divide both sides by 7 to isolate x\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x=4\" Divide\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "-----------------First Answer------------------------------\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "So the first part of our answer is: \"x=4\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Since we know that \"x=4\" we can plug it into the equation \"y=%283%2F2%29x-6\" (remember we previously solved for \"y\" in the first equation).\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y=%283%2F2%29x-6\" Start with the equation where \"y\" was previously isolated.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y=%283%2F2%29%284%29-6\" Plug in \"x=4\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y=12%2F2-6\" Multiply\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y=6-6\" Reduce\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y=0\" Combine like terms \r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "-----------------Second Answer------------------------------\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "So the second part of our answer is: \"y=0\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "-----------------Summary------------------------------\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "So our answers are:\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x=4\" and \"y=0\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "which form the point \r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Now let's graph the two equations (if you need help with graphing, check out this solver)\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "From the graph, we can see that the two equations intersect at . This visually verifies our answer.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " graph of \"3x-2y=12\" (red) and \"2x%2By=8\" (green) and the intersection of the lines (blue circle).\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( "
\n" );