x^2+ax+a-1=0
D>0
D=a^2-4*(a-1)=a^2-4a+4>0
a^2-4a+4=0
D=16-16=0
a= -b/2a= 4/2 = 2
(a-2)^2>0
a∈(-∞, 2)⋃(2, ∞)
x^2+ax+a-1=0
D>0
D=a^2-4*(a-1)=a^2-4a+4>0
a^2-4a+4=0
D=16-16=0
a= -b/2a= 4/2 = 2
(a-2)^2>0
a∈(-∞, 2)⋃(2, ∞)
a^2-4a+4>0
d=16-16=0
a=-b/2a=4/2=2
при a>2