[tex]t^4 - 4*t^3 - 14*t^2 + 36*t + 45 \ \textless \ 0[/tex]

t³(t-3)-t²(t-3)-17t(t-3)-15(t-3)<0(t-3)(t³-t²-17t-15)<0(t-3)[t²(t+3)-4t(t+3)-5(t+3)]<0(t-3)(t+3)(t²-4t-5)<0(t-3)(t+3)[t(t+1)-5(t+1)]<0(t-3)(t+3)(t+1)(t-5)<0t=3  t=-3  t=-1  t=5         +                _                  +                  _                  +----------(-3)------------(-1)-----------(3)--------------(5)-----------------t∈(-3;-1) U (3;5)