document.write( "Question 152225: factor: x^2-5x+6\r
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Algebra.Com's Answer #111889 by nabla(475)![]() ![]() ![]() You can put this solution on YOUR website! x^2-5x+6=(x-3)(x-2)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Explanation:\r \n" ); document.write( "\n" ); document.write( "A 2nd degree polynomial (ax^2+bx+c) will factor, if factorisable, to form (1) (dx+e)(fx+g). Now, if we apply foil to (1), we get eg+(ef+dg)x+df x^2\r \n" ); document.write( "\n" ); document.write( "Now, \n" ); document.write( "eg=c \n" ); document.write( "ef+dg=b \n" ); document.write( "df=a\r \n" ); document.write( "\n" ); document.write( "In words, we want two numbers e,g such that e*g equal the constant term of the original polynomial.\r \n" ); document.write( "\n" ); document.write( "Moreover, we want numbers d,f such that d*f equals the coefficient of the x^2 term in the original polynomial.\r \n" ); document.write( "\n" ); document.write( "Finally, we want two numbers f,d such that ef+dg equals the coefficient of the x term in the original polynomial.\r \n" ); document.write( "\n" ); document.write( "As you can see, e and g give us the most useful information. We find e and g by looking at the factors of c.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "For your polynomial, c is 6. The factors of 6 are 1,2,3,6. \n" ); document.write( "Now, for your polynomial, a is 1. 1 is the only factor of 1.\r \n" ); document.write( "\n" ); document.write( "So we need numbers out of 1,2,3,6 that add to equal -5. We can see right away that -2+-3=-5. So these must be our f and g. So it factors as (x-3)(x-2) \n" ); document.write( " |