E1.x²=-32=>x=16
E2.x²+x+1=0
∆=b²+4ac=1²+4•1•1=1+4=5
X1=-b-√∆/2a=-1-√5/2
X2=-b+√∆/2a=-1+√5/2
x1+x2=-1-√5/2-1+√5/2=-1-√5-1+√5(totul supra 2 pentru ca e numitor comun)=-2/2(deoarece-√5 si +√5 se simplifica si -1-1 este -2)=1
E3.x²-4x+7=0
∆=(-4)²+4•1•7=16+28=44
X1=4-√44/2
X2=4+√44/2
X1²+X2²=(4-√44/2)²+(4+√44/2)²=16-44/4+16+44/4(44se reduc)=32/4=8
