From the diagram, find the coordinates of the vertex of this parabola and the x-coordinates of the two zeros (where the graph crosses the x-axis.). Estimate the y-coordinate of the y-intercept, (0, b).
Decide which of the following quadratic equations would serve you best in attacking this problem:
y-k = a(x-h)^2 In this case, (h,k) represents the vertex of your parabola.
y=ax^2+bx+c This is the most general quadratic equation. If you know 3 points on the graph (which you do), you can then find the values of the 3 coefficients a, b and c. This is "standard form."
Please share your work. Will then be happy to comment on what you've done and make suggestions.