document.write( "Question 61715: Can you help me please\r
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document.write( "Find all three zeros of f(x)=x^3-4X^2+13x+50 given that 3+4i is a zero \r
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document.write( "thank you \n" );
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Algebra.Com's Answer #42506 by jai_kos(139)![]() ![]() ![]() You can put this solution on YOUR website! F(x) = x^3 - 4x^2 + 13 x + 50 ---->(1) \n" ); document.write( "Check the last number, which is 50 \n" ); document.write( "Now find the factors of 50, \n" ); document.write( "That is 50 ---- 1 , 2 , 5 ,25 \n" ); document.write( "So take all the numbers ---- 1 , -1 ,2 ,-2 ,5,-5,25 , -25 \n" ); document.write( "Now take the first factor 1. put in equation(1), we get \n" ); document.write( "F(1) = 1^3 - 4*1^2 + 13*1+ 50 = 48 \n" ); document.write( "F(1) is not equal to zero. \n" ); document.write( "Like this find for different numbers, \n" ); document.write( "Then we find that F(-2) is equal to zero. \n" ); document.write( "So x = -2 is a zero. ------>(2) \n" ); document.write( "Now rewrite the above equation we find that... \n" ); document.write( " x+2 = 0 \n" ); document.write( " Now take this and divide equation (1), \n" ); document.write( " x^2 - 6x + 25 \n" ); document.write( " --------------------------- \n" ); document.write( "(x+2) | x^3 - 4x^2 + 13 x + 50 Subtract, we \n" ); document.write( "get \n" ); document.write( " | x^3 + 2x^2 \n" ); document.write( " | - 6x^2 +13x \n" ); document.write( " | - 6x^2 - 12x Subtract , we get \n" ); document.write( " | 25x + 50 \n" ); document.write( " 25x + 50 Subtract, we get \n" ); document.write( " 0 \r \n" ); document.write( "\n" ); document.write( "We get x^2 - 6x + 25 \n" ); document.write( "Simplify this quadratic equation, we get \n" ); document.write( "x = - (-6) +- sqrt(6^2 - 4* 1* 25 \n" ); document.write( " 2 \n" ); document.write( "x = 3 + 4i and x = 3 - 4i\r \n" ); document.write( "\n" ); document.write( "Therefore the zeroes are x = 2 and x = 3 + 4i , x = 3 - 4i\r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |