a) The parabola is open downward (its turned into the direction of the negative sector)
b) The y-intercept is the value of y when x = 0.
In this case, we have: y-intercept: 3
The x-intercept is the value of x when y = 0.
In this case, we have: x-intercepts: -6, 2
c)
The vertex is the maximum point of the parabola. In this case, the vertex is: (-2,4)
d) The axis of symmetry is the one that can divide the parabola into two equal parts whose each one is the reflection of the another over the axis.
In this case, the axis is the vertical line passing through the vertex. Therefore, the axis is x = -2