Răspuns:
f'(x) = (3/5)·5·x⁴+(3/4)·4·x³-2·3·x²+0
f'(x) =3·x⁴+3·x³-6·x²
f'(x) =3x²(x²+x-2)
f'(x) =3x²(x²-x+2x-2)
f'(x) =3x²[x(x-1)+2(x-1)]
f'(x) =3x²(x-1)(x+2)
