... 2.3 x(x + 1) x +1 0.5 20 09 x + 20 09 = 20 09 x + 2010 20 09 x + 2010 x+1 = 20 09 x + 2010 20 09- x+ 20 09 x = 20 09 x ( 20 09 x + 1) = 20 09 x = x = 20 09 (tm) ( x 20 09) 0.5 0.5 0.5 Trng THCS ... (0,5) 2008 2007 2006 2005 x + 20 09 x + 20 09 x + 20 09 x + 20 09 + = + (0,5) 2008 2007 2006 2005 (x + 20 09) ( 1 1 + )=0 2008 2007 2006 2005 (0,5) x + 20 09 = x = -20 09 b, x + x + 11 + x + x = (0,5) ... (0,5) 2008 2007 2006 2005 x + 20 09 x + 20 09 x + 20 09 x + 20 09 + = + (0,5) 2008 2007 2006 2005 (x + 20 09) ( 1 1 + )=0 2008 2007 2006 2005 (0,5) x + 20 09 = x = -20 09 b, x + x + 11 + x + x = (0,5)...