1) if roots of a equation :f(x) = a(x-2)² + k, a ≠0, are A and B, |B - A|= 12 b, find value of k ? There's no way to find a value for k. f(x) is a parabola with vertex (2,k). So its axis of symmetry is the vertical line x = 2. Its roots are A and B, so its x-intercepts are (A,0) and (B,0). Since |B - A| = 12, they are 12 units apart, so each is 6 units from the axis of symmetry, so they are (-4,0) and (8,0) So any parabola like this would do, this has vertex at (2,-12), so k = -12. There are infinitely many possibilities. There is not enough information to find k.Edwin