3х²+33х+84=0 Д= 33²-4*3*84= 1089-1008=81 х1= -33-9/ (2×3)= -42/6= -7 х2= -33+9/6=-24/6= -4
X²+11x+28=0 x1+x2=-11 U x1*x2=24⇒x1=-7 U x2=-4