document.write( "Question 127865: I need help with four problems. You have to solve each system of equations by substitutions. Te first one i need help with is x+y=1
\n" ); document.write( "2x-y=-2. The second one is 5x-3y=-11 and x-2y=2. The third one is x-y=3 and 6x+4y=13. The fourth one is 2x-y=16 and -x+2y=-8. I have no clue how to do these problems so i need help.
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Algebra.Com's Answer #93665 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
I'll do the first two to get you started\r
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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%28x%2By=1%2C2x-y=-2%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( "\"x%2By=1\" Start with the first equation\r
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\n" ); document.write( "\n" ); document.write( "\"y=1-x\" Subtract \"x\" from both sides\r
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\n" ); document.write( "\n" ); document.write( "\"y=-x%2B1\" Rearrange the equation\r
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\n" ); document.write( "\n" ); document.write( "\"y=%28-x%2B1%29%2F%281%29\" Divide both sides by \"1\"\r
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\n" ); document.write( "\n" ); document.write( "\"y=%28%28-1%29%2F%281%29%29x%2B%281%29%2F%281%29\" Break up the fraction\r
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\n" ); document.write( "\n" ); document.write( "\"y=-x%2B1\" Reduce\r
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\n" ); document.write( "\n" ); document.write( "Since \"y=-x%2B1\", we can now replace each \"y\" in the second equation with \"-x%2B1\" to solve for \"x\"\r
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\n" ); document.write( "\n" ); document.write( "\"2x-highlight%28%28-x%2B1%29%29=-2\" Plug in \"y=-x%2B1\" into the first equation. In other words, replace each \"y\" with \"-x%2B1\". 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( "\"2x%2Bx-1=-2\" Distribute the negative\r
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\n" ); document.write( "\n" ); document.write( "\"3x-1=-2\" Combine like terms on the left side\r
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\n" ); document.write( "\n" ); document.write( "\"3x=-2%2B1\"Add 1 to both sides\r
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\n" ); document.write( "\n" ); document.write( "\"3x=-1\" Combine like terms on the right side\r
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\n" ); document.write( "\n" ); document.write( "\"x=%28-1%29%2F%283%29\" Divide both sides by 3 to isolate x\r
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\n" ); document.write( "\n" ); document.write( "\"x=-1%2F3\" 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=-1%2F3\"\r
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\n" ); document.write( "\n" ); document.write( "Since we know that \"x=-1%2F3\" we can plug it into the equation \"y=-x%2B1\" (remember we previously solved for \"y\" in the first equation).\r
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\n" ); document.write( "\n" ); document.write( "\"y=-x%2B1\" Start with the equation where \"y\" was previously isolated.\r
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\n" ); document.write( "\n" ); document.write( "\"y=-%28-1%2F3%29%2B1\" Plug in \"x=-1%2F3\"\r
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\n" ); document.write( "\n" ); document.write( "\"y=1%2F3%2B1\" Multiply\r
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\n" ); document.write( "\n" ); document.write( "\"y=4%2F3\" 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=4%2F3\"\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%2F3\" and \"y=4%2F3\"\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( "# 2\r
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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%285x-3y=-11%2Cx-2y=2%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( "\"5x-3y=-11\" Start with the first equation\r
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\n" ); document.write( "\n" ); document.write( "\"-3y=-11-5x\" Subtract \"5x\" from both sides\r
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\n" ); document.write( "\n" ); document.write( "\"-3y=-5x-11\" Rearrange the equation\r
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\n" ); document.write( "\n" ); document.write( "\"y=%28-5x-11%29%2F%28-3%29\" Divide both sides by \"-3\"\r
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\n" ); document.write( "\n" ); document.write( "\"y=%28%28-5%29%2F%28-3%29%29x%2B%28-11%29%2F%28-3%29\" Break up the fraction\r
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\n" ); document.write( "\n" ); document.write( "\"y=%285%2F3%29x%2B11%2F3\" Reduce\r
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\n" ); document.write( "\n" ); document.write( "Since \"y=%285%2F3%29x%2B11%2F3\", we can now replace each \"y\" in the second equation with \"%285%2F3%29x%2B11%2F3\" to solve for \"x\"\r
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\n" ); document.write( "\n" ); document.write( "\"x-2highlight%28%28%285%2F3%29x%2B11%2F3%29%29=2\" Plug in \"y=%285%2F3%29x%2B11%2F3\" into the first equation. In other words, replace each \"y\" with \"%285%2F3%29x%2B11%2F3\". 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%28-2%29%285%2F3%29x%2B%28-2%29%2811%2F3%29=2\" Distribute \"-2\" to \"%285%2F3%29x%2B11%2F3\"\r
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\n" ); document.write( "\n" ); document.write( "\"x-%2810%2F3%29x-22%2F3=2\" Multiply\r
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\n" ); document.write( "\n" ); document.write( "\"%283%29%281x-%2810%2F3%29x-22%2F3%29=%283%29%282%29\" Multiply both sides by the LCM of 3. 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( "\"3x-10x-22=6\" Distribute and multiply the LCM to each side\r
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\n" ); document.write( "\n" ); document.write( "\"-7x-22=6\" Combine like terms on the left side\r
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\n" ); document.write( "\n" ); document.write( "\"-7x=6%2B22\"Add 22 to both sides\r
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\n" ); document.write( "\n" ); document.write( "\"-7x=28\" Combine like terms on the right side\r
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\n" ); document.write( "\n" ); document.write( "\"x=%2828%29%2F%28-7%29\" Divide both sides by -7 to isolate x\r
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\n" ); document.write( "\n" ); document.write( "\"x=-4\" 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=-4\"\r
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\n" ); document.write( "\n" ); document.write( "Since we know that \"x=-4\" we can plug it into the equation \"y=%285%2F3%29x%2B11%2F3\" (remember we previously solved for \"y\" in the first equation).\r
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\n" ); document.write( "\n" ); document.write( "\"y=%285%2F3%29x%2B11%2F3\" Start with the equation where \"y\" was previously isolated.\r
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\n" ); document.write( "\n" ); document.write( "\"y=%285%2F3%29%28-4%29%2B11%2F3\" Plug in \"x=-4\"\r
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\n" ); document.write( "\n" ); document.write( "\"y=-20%2F3%2B11%2F3\" Multiply\r
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\n" ); document.write( "\n" ); document.write( "\"y=-3\" 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=-3\"\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=-4\" and \"y=-3\"\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 \"5x-3y=-11\" (red) and \"x-2y=2\" (green) and the intersection of the lines (blue circle).\r
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