x^2+ax-1=0x^2+x+(a-2)=0
x^2+ax-1= x^2+x+(a-2)
(a-1)x=a-1
x=1
1^2+a*1-1=0 a=0
x^2-1=0 x=1OR x=-1
x^2+x-2=0x=1ORx=-2