x1+x2=2a
x1x2=-2a (Viete)
2+x2=2a
2x2=-2a=-(2+x2)
2x2=-2-x2
3x2=-2
x2=-2/3
a=(2+x2)/2=(2-2/3):2=(4/3):2=2/3
ecuiatia devine
x²-4x/3-4/3=0
verificare pt x=2
4-8/3-4/3=4-4=0 verifica
pt x=-2/3
4/9 - (4/3) *(-2/3)-4/3=4/9+8/9-4/3=12/9-4/3=4/3-4/3=0 verifica
