Hello,
Find the equation of the axis of symmetry is like find the maximum or minimum point of this function.
[tex]f(x)=2x^2+4x-3\\\\\alpha=-\dfrac{b}{2a}=-\dfrac{4}{4}=-1\\\\[/tex]
The equation of the axis of symmetry is then : [tex]x=-1[/tex]
[tex]\beta=f(\alpha)=2(-1)^2+4(-1)-3=2-4-3=-5[/tex]
Coordinates of vertex : [tex](\alpha,\beta)=(-1;-5)[/tex]
