X(X - 2009) + X - 2009 = 0X(X - 2009) + X - 2009 = 0 X(X - 2009) +( X – 2009) = 0 (X - 2009)(X + 1) = 0 (0,5Đ)2009X  1 (0,5Đ)X - 2X + 1

Bài 3 : (1 đ): Tìm x, biết : x(x - 2009) + x - 2009 = 0

x(x - 2009) + x - 2009 = 0



x(x - 2009) +( x – 2009) = 0



(x - 2009)(x + 1) = 0

(0,5đ)

2009

x









1



_(0,5đ)



  ^{ }