x1 не равно x2

x1, x2 > 1/2

(a+3) x^2+3 (a+1) x-2 (a+1) = 0

D=9 (a+1) ^2+8 (a+3) (a+1) = (a+1) (9a+9+8a+24) = (a+1) (17a+33) >0,

(a+1) (17a+33) = 0,

a1=-1 16/17, a2=-1,

a∈ (-∞; -1 16/17) U (-1; +∞),

x1+x2=-3 (a+1) / (a+3) >1/2+1/2,

-3a-3>a+3,

-4a>6,

a<-1 1/2,

x1*x2=-2 (a+1) / (a+3) >1/2*1/2,

-8a-8>a+3,

-9a>11,

a<-1 2/9,

a<-1 16/17,

a∈ (-∞; -1 16/17).