Question 320755
Complete the square to convert to vertex form, {{{y=a(x-h)^2+k}}} where (h,k) is the vertex.
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{{{f(x) = -x^2 + 4x + 5}}} 
{{{f(x) = -(x^2-4x) + 5}}}
{{{f(x) = -(x^2-4x+4) + 5+4}}}
{{{f(x) = -(x-2)^2 + 9}}}
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The vertex is (2,9)