Question

корней х1 х2 уравнения х^2+8х-1=0
Х1^2+Х2^2

Answer 1

X1^2 +X2^2=X1^2+X2^2+2X1X2-2X1X2=(X1+X2)^2-2X1X2
X1+X2=-8
X1X2= -1
(-8)^2-2(-1)=69