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How do you rewrite a quadratic formula into vertex form

User Ivan Popov
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\bf 37-6x-y+x^2=0\impliedby \textit{first off, we group the x's} \\\\\\ (x^2-6x)-y+37=0\implies (x^2-6x+\boxed{?}^2)-y+37=0 \\\\\\ \textit{now, we're missing a term for your perfect trinomial}\\ \textit{but notice, 6x is really, 2*x*3 thus} \\\\\\ (x^2-6x+\boxed{3}^2)-y+37=0 \\\\\\ \textit{now, we're borrowing from Mr zero} \\\\\\ \textit{so, if we add }3^2\textit{ we also have to subtract }3^2 \\\\\\ (x^2-6x+3^2-3^2)-y+37=0 \\\\\\ (x^2-6x+3^2)-y+37-3^2=0 \\\\\\ (x-3)^2-y+37-9=0\implies (x-3)^2+28=y

now, the vertex form of a quadratic is
\bf y=(x-{{ h}})^2+{{ k}}\\ x=(y-{{ k}})^2+{{ h}}\qquad\qquad vertex\ ({{ h}},{{ k}})

so.. in the example above, the vertex is at (3, 28) since h = 3, and k = 28

User Oleg Sevruk
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