Suppose that a and b are nonzero real numbers, and that the equation x² + ax + b = 0 has solutions a
and b. Then the pair (a, b) is

The equation has two solutions. Means Discriminant means b^2-4ac >0

Here b = a.

a = 1

c = b

a^2 - 4b >0

a=2

b= -1

then a^2 - 4b > 0 = 4+4 > 0

therefore its 2, -1