document.write( "Question 1182627: Using synthetic division, find one zero of the polynomial f(x)=x^3-21x-20 then write the polynomial in factored form based on the zero you found:
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Algebra.Com's Answer #812716 by Edwin McCravy(20060)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "The potential zeros have numerators which are divisors of the last term in\r\n" );
document.write( "absolute value, 21 and denominators which are divisors of the leading\r\n" );
document.write( "coefficient 1.  So all potential divisors are: \r\n" );
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document.write( "Try 1\r\n" );
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document.write( "1 | 1 0 -21 -20\r\n" );
document.write( "  |   1   1 -20 \r\n" );
document.write( "    1 1 -20 -40\r\n" );
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document.write( "That left remainder -40, not 0, so we try the next one, -1\r\n" );
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document.write( "-1 | 1  0 -21 -20\r\n" );
document.write( "   |   -1   1  20 \r\n" );
document.write( "     1 -1 -20   0\r\n" );
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document.write( "That left remainder 0, so -1 is a zero, and (x+1) is a factor.\r\n" );
document.write( "The other three numbers on the bottom row give us the coefficients\r\n" );
document.write( "of the other factor, (1x2-1x-20).  So f(x) factors as\r\n" );
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document.write( "\"f%28x%29=%28x%5E%22%22%2B1%29%28x%5E2-x-20%29\"\r\n" );
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document.write( "We can further factor the quadratic in the second parentheses:\r\n" );
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document.write( "\"f%28x%29=%28x%5E%22%22%2B1%29%28x%5E%22%22-5%29%28x%5E%22%22%2B4%29\"\r\n" );
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document.write( "The zeros of f(x) are found by setting each factor = 0\r\n" );
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document.write( "x+1=0 ;  x-5=0;  x+4=0\r\n" );
document.write( "  x=-1;    x=5     x=-4\r\n" );
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document.write( "The graph shows that these three zeros are at the 3 x-intercepts:\r\n" );
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document.write( "\"graph%28400%2C400%2C-10%2C10%2C-60%2C20%2C+x%5E3-21x-20%29\"\r\n" );
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document.write( "Edwin
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