We can do this by using the formula x = -b/2a, where a = -1 and b = 4:
x = -4/(2*(-1)) = 2
So the vertex is at (2, f(2)). To find the y-coordinate of the vertex, we can plug in x = 2:
f(2) = -2^2 + 4(2) = 0
Therefore, the vertex is at (2, 0).
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