g(x) is 0 when x = -3 and 3 so g(x) passes though x axis at x = -3 and x = 3
At x = 0 g(x) = 9 so it also passes through (0,9) and its symmetrical about the y axis The vertex is at (09)
so we can write it as g(x) = a(x - 0)^2 + 9
plugging in the point (2,5) 5 = 4a + 9
4a = -4 so a = -1
and the equation of the parabola is g(x) = -x^2 + 9
