Answer
Please see the graph.
Work Step by Step
$y=3x^2-6x$
vertex:
$x=-b/2a$
$x=-(-6)/2(3)$
$x = 6/6 = 1$
$y = 3x^2-6x$
$y=3*1^2-6*1$
$y=3*1-6$
$y=3-6 = -3$
One other point on the curve:
$x=0$
$y=3x^2-6x$
$y=3*0^2-6*0$
$y=3*0-0$
$y=0-0 = 0$
The blue line is the axis of symmetry.