Tìm x, biết: x²(x-2x³)

a) x²(x-2x³)
b) (x²+1)(5-x)
c) (x-2)(x²+3x-4)
d) (x-2)(x-x²+4)
e) (x²-1)(x²+2x)
f) (2x-1)(3x+2)(3-x)
g) (x+3)(x²+3x-5)
h) (xy-2)+(x³-2x-6)
i) (5x³-x²+2x-3)(4x²-x+2)