Answer the question using the symmetry of the parabola and the vertex form of the equation of a parabola,
where (h,k) is the vertex.
(1) With x-intercepts 3 and 9, the axis of symmetry is x=6, so the equation is of the form
(2) Use one of the x-intercepts and the third point in that equation to find the value of a:
(9,0) --> 0 = a(3^2)+k 9a+k = 0
(10,-7) --> -7 = a(4^2)+k 16a+k = -7
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7a = -7
a = -1
The equation is now of the form
(3) Use either x-intercept to find k:
We are done....
ANSWER: