Question 1179958
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You have two answers that both use valid algebraic techniques to find the answer.<br>
You should understand those algebraic methods.  However, you should know that all the work they did to answer this question was a waste of time.<br>
The zeros of the function are 3 and 9, so the axis if symmetry is x=6.  So if the graph passes through (6,11), then (6,11) is the vertex.<br>
ANSWER: (in a few seconds, without algebra) The vertex is (6,11).<br>