document.write( "Question 554379: Find the equations of the tangent line and normal line to the graph of 6x^2-2xy+y^3=9 at the point (2,-3) \n" ); document.write( "
Algebra.Com's Answer #361320 by Edwin McCravy(20056)\"\" \"About 
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document.write( "6x² - 2xy + y³ = 9\r\n" );
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document.write( "Find the derivative implicitly term by term:\r\n" );
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document.write( "12x - 2(x\"%28dy%29%2F%28dx%29\" + y) + 3y²\"%28dy%29%2F%28dx%29\" = 0\r\n" );
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document.write( "Solve for \"%28dy%29%2F%28dx%29\"\r\n" );
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document.write( "12x - 2x\"%28dy%29%2F%28dx%29\" - 2y + 3y²\"%28dy%29%2F%28dx%29\" = 0\r\n" );
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document.write( "Isolate the terms in \"%28dy%29%2F%28dx%29\" \r\n" );
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document.write( "-2x\"%28dy%29%2F%28dx%29\" + 3y²\"%28dy%29%2F%28dx%29\" = -12x + 2y\r\n" );
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document.write( "\"%28dy%29%2F%28dx%29\"(-2x + 3y²) = -12x + 2y\r\n" );
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document.write( "\"%28dy%29%2F%28dx%29\" = \"%28-12x%2B2y%29%2F%28-2x%2B3y%5E2%29\"\r\n" );
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document.write( "Write the positive terms first\r\n" );
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document.write( "\"%28dy%29%2F%28dx%29\" = \"%282y-12x%29%2F%283y%5E2-2x%29\"\r\n" );
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document.write( " = \"%282%28-3%29-12%282%29%29%2F%283%28-3%29%5E2-2%282%29%29\" = \"%28-6-24%29%2F%283%289%29-4%29\" = \"%28-30%29%2F%2827-4%29\" = \"%28-30%29%2F23\" = \"-30%2F23\"\r\n" );
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document.write( "Finding the tangent line is the algebra problem of finding the equation \r\n" );
document.write( "of the line through the point (2,-3) with a slope of \"-30%2F23\"\r\n" );
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document.write( "The equation of the tangent line at (2,-3) is\r\n" );
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document.write( "y = \"-30%2F23\"x - \"9%2F23\"\r\n" );
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document.write( "Finding the normal line is the algebra problem of finding the equation \r\n" );
document.write( "of the line through the point (2,-3) with a slope of \"23%2F30\"\r\n" );
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document.write( "The equation of the normal line at (2,-3) is\r\n" );
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document.write( "y = \"23%2F30\"x - \"68%2F15\"\r\n" );
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document.write( "Edwin
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