[tex]\it \forall x\in\mathbb{R},\ f(x)<0 \Leftrightarrow\begin{cases}\it m<0\ \ \ \ \ (1)\\ \\ \it \Delta<0\ \ \ \ \ (2)\end{cases}\\ \\ \\ (2) \Rightarrow m^2-m(m-1)<0 \Rightarrow m^2-m^2+m<0 \Rightarrow m<0\\ \\ \\ Deci,\ \forall x\in\mathbb{R},\ f(x)<0 \ pentru\ m\in(-\infty,\ \ 0)[/tex]
