Question

What is the equation of the line of symmetry for the graph of y = -2(x - 4)2 + 3?

x = -2
x = 2
x = 3
x = 4

Answer 1

The line of symmetry is the line that splits the graph in half symmetrically. This is an x^2 parabola, so it looks like this:

Answer 2

That is how you can tell the line of symmetry...it is the value in the "middle" of the graph. In this case, in your equation the (x-4) gives you your line of symmetry. It is x = 4 and the graph looks (sort of) like the one I drew.