Explanation:
When we reflect over the vertical y axis, every negative x value becomes positive and vice versa. So we effectively replace x with -x like so
f(x) = -5x+9
f(-x) = -5(-x)+9 ... replace every x with -x
f(-x) = 5x+9
g(x) = 5x+9
A point like (1,4) on f(x) will reflect over to (-1,4) on g(x). If we apply this to every point on f(x), then all of f(x) will reflect to g(x).
