first find the vertex
the x coordinate of the vertex is the axis of symmetry
the vertex of an equation in form
y=ax^2+bx+c is
-b/2a=x coordinate
y=1x^2+4x-7
vertex=-4/2=-2
axis of symmetry is x=-2
y=2x^2+3x-4
ertex=-3/(2*2)=-3/4
axis of symmetry is x=-3/4