Quadratics practice, I need help on how to solve this

Below in bold.

Step-by-step explanation:

x^2 - 2x - 3 = 0

(x - 3)(x + 1) = 0

The zeroes are -1, 3.

Change to vertex form:

= (x - 1)^2 - 1 - 3

= (x - 1)^2 - 4

So the axis of symmetry is x = 1.

The vertex is at (1, -4)  and it is a minimum (because the coefficient of x^2 is positive).

Domain is  (-∞, ∞)

Range is [-4, ∞).

Increasing  when x < 1.

Decreasing  when x > 1.

End behaviour x -∞ , y --> ∞

x > ∞, y --->  ∞