document.write( "Question 1067167: Find a formula for the polynomial f(x) of least degree that passes through the points (-4,0) , (5,0), and (0,-9). \n" ); document.write( "

Algebra.Com's Answer #682363 by Edwin McCravy(20056) $\"\"$ $\"About$

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document.write( "(-4,0) , (5,0), and (0,-9)\r\n" );
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document.write( "Since the y-coordinate of the first two points are 0,\r\n" );
document.write( "-4 and 5 are zeros, then f(-4)=0 and f(5)=0\r\n" );
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document.write( "So f(x) has factors (x+4) and (x-5)\r\n" );
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document.write( "So we know the polynomial f(x) is of the form \r\n" );
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document.write( "f(x) = k(x+4)(x-5)  for some value k\r\n" );
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document.write( "We know that f(0) = -9\r\n" );
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document.write( "So\r\n" );
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document.write( "f(0) = k(0+4)(0-5) = k(4)(-5) = -20k = -9\r\n" );
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document.write( "                                   k = \r\n" );
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document.write( "So f(x) = (x+4)(x-5)\r\n" );
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document.write( "Edwin

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