document.write( "Question 198572: Could someone help me with these, I had it last year but forgot how it works:\r
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document.write( "1) Find a quadratic equation with roots (4+i)and(4-i).
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document.write( "2) Given the equation x^3-2x^2+x-3=0, what are the possible rational roots??
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document.write( "3) Find the irratinal roots of the equation; x^3-4x^2+2x+1=0 I should use the quadratic formula to solve the equation, it might sound stupid but I never really understood how to use the quadratic formula =( \r
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Algebra.Com's Answer #149093 by jim_thompson5910(35256)![]() ![]() ![]() You can put this solution on YOUR website! \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Since the equations are the same, we can focus on one equation:\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "So the quadratic with the roots 4+i and 4-i is \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "# 2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Any rational zero can be found through this equation\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "So let's list the factors of -3 (the last coefficient):\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now let's list the factors of 1 (the first coefficient):\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now let's divide each factor of the last coefficient by each factor of the first coefficient\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now simplify\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "These are all the distinct rational zeros of the function that could occur\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "# 3\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "First, let's find the possible rational zeros\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Any rational zero can be found through this equation\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "So let's list the factors of 1 (the last coefficient):\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now let's list the factors of 1 (the first coefficient):\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now let's divide each factor of the last coefficient by each factor of the first coefficient\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now simplify\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "These are all the distinct rational zeros of the function that could occur\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Let's see if the possible zero \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "So let's make the synthetic division table for the function \n" ); document.write( "\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Since the remainder \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Take note that the first three values in the bottom row are 1, -3, and -1. So this means that\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now all we need to do is solve \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Notice we have a quadratic in the form of \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Let's use the quadratic formula to solve for \"x\":\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "So the next two zeros are \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "===================================================================================\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Answer:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "So the three roots are \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "where the irrational roots are \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |