easy
ok so the x value of the vertex which is also the axis of symetry can by found by -b/2a when you have the equation in form
y=ax^2+bx+c
y=2x^2+4x-3
xvaleuvertex=-4/(2*2)=-4/4=-1
the axis of symmetry is x=-1
plug x=-1 back into the origianl equation to find the y alue for the vertex
y=2(-1)^2+4(-1)-3
y=2(1)-4-3
y=2-7
y=-5
vertex is (-1,-5)
axis of symmetry is x=-1