document.write( "Question 1048804: Please help me solve this equation
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document.write( " Solve the inequality.
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document.write( "(x - 5)(x^2 + x + 1) > 0 \n" );
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Algebra.Com's Answer #664373 by Theo(13342)![]() ![]() You can put this solution on YOUR website! set the equation equal to 0. \n" ); document.write( "you get (x-5) * (x^2 + x + 1) = 0 \n" ); document.write( "this is true if (x-5) = 0 and/or if (x^2 + x + 1) = 0\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x-5 = 0 when x = 5.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "this means that x-5 is negative when x < 5 and x-5 is positive when x > 5.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x^2 + x + 1 never equals 0. \n" ); document.write( "in fact, it is always positive.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "since x^2 + x + 1 = 0 is a quadratic equation in standard form, then it has a max/min point at x = -b/2a.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "since a = 1 and b = 1 and c = 1, that max/min point will be at x = -1/2.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "when x = -1/2, the max/min point will be at y = (-1/2)^2 - 1/2 + 1 which will be at y = 1/4 - 1/2 + 1 which becomes y = 3/4.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "since the coefficient of the x^2 term is positive, then x = -1/2 is a min point and the equation opens up.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "that says that all values of y = x^2 + x + 1 are positive regardless of the value of x.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "not only are they all positive, but they are all greater than or equal to 3/4.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "since x^2 + x + 1 is always positive and since x-5 is positive when x > 5 and negative when x < 5, then:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "(x-5) * (x^2 + x + 1) is positive when x > 5 because positive times positive always gives a positiv \n" ); document.write( "e result.\r \n" ); document.write( "\n" ); document.write( "(x-5) * (x^2 + x + 1) is negative when x < 5 because positive times negative always give a negative result.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "your solution is that (x-5) * (x^2 + x + 1) > 0 when x > 5.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the following graph confirms that this is true.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " ![]() \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "here's the graph of x-5 by itself.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " ![]() \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "here's the graph of x^2 + x + 1 by itself.\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( " |