Question 148667
Find the vertex of quadratic equation f(x) = 2x^2 + 4x-9
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It looks like you are trying to complete the square:
2x^2+4x = y+9
2(x^2+2x+1) = y+9+2
2(x+1)^2 = y+11
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Vertex is at (-1,-11)
{{{graph(400,300,-10,10,-15,50,2x^2+4x-9)}}}
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Cheers,
Stan H.