document.write( "Question 850858: Find the equation of the line that passes through (-8, 2) and (5, -7). \n" ); document.write( "
Algebra.Com's Answer #523013 by Edwin McCravy(20055)\"\" \"About 
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document.write( "First we use the slope formula:\r\n" );
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document.write( "m = \"%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29\"\r\n" );
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document.write( "where (x1,y1) = (-8, 2) \r\n" );
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document.write( "and where (x2,y2) = (5, -7).\r\n" );
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document.write( "m = \"%28%28-7%29-%282%29%29%2F%28%285%29-%28-8%29%29\"\r\n" );
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document.write( "m = \"%28-7-2%29%2F%285%2B8%29\"\r\n" );
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document.write( "m = \"%28-9%29%2F13\" = \"-9%2F13\"\r\n" );
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document.write( "Then we use the point-slope formula:\r\n" );
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document.write( "y - y1 = m(x - x1)\r\n" );
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document.write( "where (x1,y1) = (-8, 2)\r\n" );
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document.write( "and m = \"-9%2F13\"\r\n" );
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document.write( "y - y1 = m(x - x1)\r\n" );
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document.write( "y - 2 = \"-9%2F13\"(x - (-8))\r\n" );
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document.write( "y - 2 = \"-9%2F13\"(x + 8)\r\n" );
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document.write( "Multiply both sides by 13 to clear the fraction:\r\n" );
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document.write( "13(y - 2) = 13·\"-9%2F13\"(x + 8) \r\n" );
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document.write( "13y - 26 = -9(x + 8)\r\n" );
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document.write( "13y - 26 = -9x - 72\r\n" );
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document.write( "9x + 13y = -46  < -- that's standard form.\r\n" );
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document.write( "or solve for y:\r\n" );
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document.write( "     13y = -9x - 46\r\n" );
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document.write( "     \"13y%2F13\" = \"-9%2F13\"x - \"46%2F13\"\r\n" );
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document.write( "     y = \"-9%2F13\"x - \"46%2F13\"   < --- that's slope intercept form.\r\n" );
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document.write( "Edwin
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