Tìm x biết

2x^2 (x+1) - x(x+1) =0

x(x-7)- 2(7 - x) = 0

2x (x-2) - (x - 2)^2  = 0

-4x^2  (x - 1) - 6x (1 - x) = 0

3x(x + 2) + 5(x - 2) = 0

x(x-1) + (1- x)^2 = 0