[tex]\displaystyle Din~relatiile~lui~Viete~avem~x_1+x_2+x_3=0. \\ \\ Cum~x_1+x_2=x_3,~avem~x_1+x_2+x_3=2x_3. \\ \\ Deci~2x_3=0 \Rightarrow x_3=0. \\ \\ Deci~o~radacina~a~polinomului~este~0,~ceea~ce~inseamna~ca \\ \\ f(0)=0 \Leftrightarrow -m=0 \Leftrightarrow m=0.[/tex]