X^2+(a-b)x+(1-a-b)=0. Find value of 'a' if roots are imaginary.

Answer 1

if the roots are imaginary (not complex), there is no x term. So a=b
If there are no real roots, the discriminant is negative. So
-4(1-2a) < 0
a < 1/2

So, pick any value for a < 1/2, say, a = -1
Then b = -1 and x^2 +3 = 0

Answer 2

Thank you