SOLUTION: what is the vertex of f(x)=-2x^2+2x+5

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Question 960056: what is the vertex of f(x)=-2x^2+2x+5
Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!
first write it in the vertex form f%28x%29=%28x-h%29%5E2%2Bk where h and k are x and y coordinates of the vertex
f%28x%29=-2x%5E2%2B2x%2B5....f%28x%29=y
y=-%282x%5E2-2x%29%2B5
y=-2%28x%5E2-x%2B_%29-%28-2%29%2A_%2B5....complete square
y=-2%28x%5E2-x%2B%281%2F2%29%5E2%29-%28-2%29%2A%281%2F2%29%5E2%2B5
y=-2%28x-1%2F2%29%5E2%2Bcross%282%29%281%2Fcross%284%292%29%2B5
y=-2%28x-1%2F2%29%5E2%2B%281%2F2%29%2B10%2F2
y=-2%28x-1%2F2%29%5E2%2B11%2F2=> h=1%2F2 and k=11%2F2
so vertex is at (1%2F2,11%2F2)