document.write( "Question 170422: Plot the graph of the equations 4x - 6y = 2 and 2x - 3y = 1 and interpret the result.
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Algebra.Com's Answer #125817 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!

Graphing the first equation

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\n" ); document.write( "\n" ); document.write( "In order to graph \"4x-6y=2\", we need to solve for \"y\" first.\r
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\n" ); document.write( "\n" ); document.write( "\"4x-6y=2\" Start with the first equation.\r
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\n" ); document.write( "\n" ); document.write( "\"-6y=2-4x\" Subtract \"4x\" from both sides.\r
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\n" ); document.write( "\n" ); document.write( "\"-6y=-4x%2B2\" Rearrange the terms.\r
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\n" ); document.write( "\n" ); document.write( "\"y=%28-4x%2B2%29%2F%28-6%29\" Divide both sides by \"-6\" to isolate y.\r
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\n" ); document.write( "\n" ); document.write( "\"y=%28%28-4%29%2F%28-6%29%29x%2B%282%29%2F%28-6%29\" Break up the fraction.\r
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\n" ); document.write( "\n" ); document.write( "\"y=%282%2F3%29x-1%2F3\" Reduce.\r
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\n" ); document.write( "\n" ); document.write( "In order to graph this equation, we only need two points to create a straight line\r
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\n" ); document.write( "\n" ); document.write( "--------------------------------Let's find the first point--------------------------------\r
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\n" ); document.write( "\n" ); document.write( "\"y=%282%2F3%29x-1%2F3\" Start with the given equation\r
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\n" ); document.write( "\n" ); document.write( "\"y=%282%2F3%29%285%29-1%2F3\" Plug in \"x=5\" \r
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\n" ); document.write( "\n" ); document.write( "\"y=10%2F3-1%2F3\" Multiply \"2%2F3\" and \"5\" to get \"10%2F3\"\r
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\n" ); document.write( "\n" ); document.write( "\"y=9%2F3\" Subtract \r
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\n" ); document.write( "\n" ); document.write( "So when \"x=5\", we have the value \"y=3\". This means we have the first point \r
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\n" ); document.write( "\n" ); document.write( "--------------------------------Let's find the second point--------------------------------\r
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\n" ); document.write( "\n" ); document.write( "\"y=%282%2F3%29x-1%2F3\" Start with the given equation\r
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\n" ); document.write( "\n" ); document.write( "\"y=%282%2F3%29%28-1%29-1%2F3\" Plug in \"x=-1\" \r
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\n" ); document.write( "\n" ); document.write( "\"y=-2%2F3-1%2F3\" Multiply \"2%2F3\" and \"-1\" to get \"-2%2F3\"\r
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\n" ); document.write( "\n" ); document.write( "\"y=-1\" Subtract\r
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\n" ); document.write( "\n" ); document.write( "So when \"x=-1\", we have the value \"y=-1\". This means we have the second point \r
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\n" ); document.write( "\n" ); document.write( "So we have the two points: and \r
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\n" ); document.write( "\n" ); document.write( "Now plot these two points on a coordinate system\r
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\n" ); document.write( "\n" ); document.write( "Now draw a straight line through the two points. This line is the graph of \"y=%282%2F3%29x-1%2F3\"\r
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\n" ); document.write( "\n" ); document.write( " Graph of \"y=%282%2F3%29x-1%2F3\" through the two points and \r
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Graphing the second equation

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\n" ); document.write( "\n" ); document.write( "\"2x-3y=1\" Start with the second equation.\r
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\n" ); document.write( "\n" ); document.write( "\"-3y=1-2x\" Subtract \"2x\" from both sides.\r
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\n" ); document.write( "\n" ); document.write( "\"-3y=-2x%2B1\" Rearrange the terms.\r
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\n" ); document.write( "\n" ); document.write( "\"y=%28-2x%2B1%29%2F%28-3%29\" Divide both sides by \"-3\" to isolate y.\r
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\n" ); document.write( "\n" ); document.write( "\"y=%28%28-2%29%2F%28-3%29%29x%2B%281%29%2F%28-3%29\" Break up the fraction.\r
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\n" ); document.write( "\n" ); document.write( "\"y=%282%2F3%29x-1%2F3\" Reduce.\r
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\n" ); document.write( "\n" ); document.write( "Take note that this equation is EXACTLY identical to the equation we just plotted. So the graph of \"y=%282%2F3%29x-1%2F3\" (and \"2x-3y=1\") is \r
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\n" ); document.write( "\n" ); document.write( "Now graphing the two equations together gives you\r
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\n" ); document.write( "\n" ); document.write( "Note: there are really two equations here. One is just right on top of the other (which hides it)\r
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\n" ); document.write( "\n" ); document.write( "Since one equation is right on top of the other, this tells us that there are an infinite number of solutions (since there are an infinite number of intersections).\r
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\n" ); document.write( "\n" ); document.write( "So the system is dependent.
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