document.write( "Question 140614: what is (12, 5) and (-4, 1) \n" ); document.write( "
Algebra.Com's Answer #102357 by jim_thompson5910(35256)\"\" \"About 
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Do you want to find the equation through these points?\r
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\n" ); document.write( "\n" ); document.write( "First lets find the slope through the points (\"12\",\"5\") and (\"-4\",\"1\")\r
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\n" ); document.write( "\n" ); document.write( "\"m=%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29\" Start with the slope formula (note: is the first point (\"12\",\"5\") and is the second point (\"-4\",\"1\"))\r
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\n" ); document.write( "\n" ); document.write( "\"m=%281-5%29%2F%28-4-12%29\" Plug in \"y%5B2%5D=1\",\"y%5B1%5D=5\",\"x%5B2%5D=-4\",\"x%5B1%5D=12\" (these are the coordinates of given points)\r
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\n" ); document.write( "\n" ); document.write( "\"m=+-4%2F-16\" Subtract the terms in the numerator \"1-5\" to get \"-4\". Subtract the terms in the denominator \"-4-12\" to get \"-16\"\r
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\n" ); document.write( "\n" ); document.write( "\"m=1%2F4\" Reduce\r
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\n" ); document.write( "\n" ); document.write( "So the slope is\r
\n" ); document.write( "\n" ); document.write( "\"m=1%2F4\"\r
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\n" ); document.write( "\n" ); document.write( "Now let's use the point-slope formula to find the equation of the line:\r
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\n" ); document.write( "\n" ); document.write( "------Point-Slope Formula------
\n" ); document.write( "\"y-y%5B1%5D=m%28x-x%5B1%5D%29\" where \"m\" is the slope, and is one of the given points\r
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\n" ); document.write( "\n" ); document.write( "So lets use the Point-Slope Formula to find the equation of the line\r
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\n" ); document.write( "\n" ); document.write( "\"y-5=%281%2F4%29%28x-12%29\" Plug in \"m=1%2F4\", \"x%5B1%5D=12\", and \"y%5B1%5D=5\" (these values are given)\r
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\n" ); document.write( "\n" ); document.write( "\"y-5=%281%2F4%29x%2B%281%2F4%29%28-12%29\" Distribute \"1%2F4\"\r
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\n" ); document.write( "\n" ); document.write( "\"y-5=%281%2F4%29x-3\" Multiply \"1%2F4\" and \"-12\" to get \"-12%2F4\". Now reduce \"-12%2F4\" to get \"-3\"\r
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\n" ); document.write( "\n" ); document.write( "\"y=%281%2F4%29x-3%2B5\" Add \"5\" to both sides to isolate y\r
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\n" ); document.write( "\n" ); document.write( "\"y=%281%2F4%29x%2B2\" Combine like terms \"-3\" and \"5\" to get \"2\" \r
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\n" ); document.write( "\n" ); document.write( "So the equation of the line which goes through the points (\"12\",\"5\") and (\"-4\",\"1\") is:\"y=%281%2F4%29x%2B2\"\r
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\n" ); document.write( "\n" ); document.write( "The equation is now in \"y=mx%2Bb\" form (which is slope-intercept form) where the slope is \"m=1%2F4\" and the y-intercept is \"b=2\"\r
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\n" ); document.write( "\n" ); document.write( "Notice if we graph the equation \"y=%281%2F4%29x%2B2\" and plot the points (\"12\",\"5\") and (\"-4\",\"1\"), we get this: (note: if you need help with graphing, check out this solver)\r
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\n" ); document.write( "\n" ); document.write( " Graph of \"y=%281%2F4%29x%2B2\" through the points (\"12\",\"5\") and (\"-4\",\"1\")\r
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\n" ); document.write( "\n" ); document.write( "Notice how the two points lie on the line. This graphically verifies our answer.
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