Question 1115837
If you will complete the square and put into other form, you can easily read the zeros and the vertex.


Alternatively you can find the zeros from general formula.


Zeros:

{{{(-4+- sqrt(16-4*2))/2}}}


{{{(-4+- sqrt(8))/2}}}


{{{(-4+- 2*sqrt(2))/2}}}


{{{-2+- sqrt(2)}}}

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And you can see that vertex is at   {{{-2}}}.


{{{graph(300,300,-5,3,-3,5,x^2+4x+2)}}}