Explanation:
f(-x) reflects the original f(x) across the y-axis.
every functional value for a positive x becomes now the functional value of the corresponding negative x. and vice versa.
and f(x) - 3 reduces all the regular functional values by 3.
so, e.g. instead of 5 the y value is then 5-3 = 2.
so, the vertex of g(x) = (-3, 2).
because g(-3) = f(- -3) - 3 = f(3) - 3 = 5 - 3 = 2.
remember, the vertex is a point on the curve and must therefore satisfy the functional expression for the x and y (coordinates) relationship.