Giải phương trình

a) (2x +1)(3 – x)(4 - 2x) = 0                                b)2x(x – 3) + 5(x – 3) = 0

c) (x2 – 4) – (x – 2)(3 – 2x) = 0                           d) x2 – 5x + 6 = 0 

e) (2x + 5)2 = (x + 2)2                                          f) 2x3 + 6x2 = x2 + 3x