Ex 2
Va rog
Dau coroana

4x² +4x+5=0 => x₁²+x₂²=S² -2P unde S=x₁+x₂=-b/a=-4/4=-1 si P=x₁·x₂=c/a=5/4 =>
x₁²+x₂²=(-1)² -5/2) =1 -5/2 =-3/2 ;
x₁²+x₂²+2x₁+2x₂+4x₁x₂=-3/2 +2·(-1) +5=-3/2 -2+5=-3/2 +3=3/2 .