The formula to find the discriminant equals D = b^2-4ac.
(Quadratic equations have the formula ax^2+bx+c. A = -1, B = +4, C = -2.)
D = 4^2-4(-1)(-2). 8-8 = 0.
0 = 1 solution
-D = 0 solutions
+D = 2 solutions
The discriminant equals 0, also establishing that if you were asked to find the solutions, there would only be one.
