Sangeetha Pulapaka

Options A, B, D, E are the quadratic expressions in vertex form.

The vertex form of a parabola is y = a(x-h)^{2} + k where (h, k) is the vertex of the parabola. a can be a positive number of a negative number. A negative number or when a < 0, indicates that the parabola opens downwards and a positive number or when a > 0 indicates that the parabola opens upwards. h, and k are the constants.

Option C is in a quadratic form and not a vertex form

x(x-1) is not in vertex form because here, a = x, a cannot be a variable, it can only be a constant.

Read more about the vertex form of a parabola: