<PRE><B>Question 145727</B>
{{{f(x)=-x^2-6x+3}}} Start with the given function



{{{f(-3)=-(-3)^2-6(-3)+3}}} Plug in {{{x=-3}}} (which is the x-coordinate of the vertex)



{{{f(-3)=-9-6*-3+3}}} Raise -3 to the 2nd power to get 9



{{{f(-3)=-9--18+3}}} Multiply 6 and -3 to get -18



{{{f(-3)=-9+18+3}}} Rewrite {{{-9--18+3}}} as {{{-9+18+3}}}



{{{f(-3)=9+3}}} Add -9 and 18 to get 9



{{{f(-3)=12}}} Add 9 and 3 to get 12



So when {{{x=-3}}}, we have {{{y=12}}}



This means that the vertex is (-3,12)
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