Tìm x; biết:

f.x³ – 7x² = – 6x                                           g.(x + 1)(x + 2)(x + 4)(x + 5) = 4              

     h.(x² – 0,5) : 2x – (3x – 1)² : (3x – 1) = 0

     i. (x + 3)(x² – 3x + 9) – x(x – 2)(x + 2) = 15