D=(a+3)²-4(a²+a+1)=a²+6a+9-4a²-4a-4=-3a²+2a+5>0
3a²-2a-5<0<br>D=4+60=64
a1=(2-8)/6=-1 U a2=(2+8)/6=5/3
a∈(-1;5/3)
{x1+x2=-a-3⇒3x2+x2=-a-3⇒4x2=-a-3⇒x2=(-a-3)/4
{x1*x2=a²+a+1
3x2*x2=a²+a+1
3x2²=a²+a+1
3*(-a-3)²/16=a²+a+1
16a²+16a+16-3a²-18a-27=0
13a²-2a-11=0
D=4+572=576
a1=(2-24)/26=-11/13
x2=(11/13-3)/4=-2 2/13:4=-28/52=-7/13⇒x1=-21/13
a2=(2+24)/26=1
x2=(-1-3)/4=-1⇒x1=-3