Problem:

Suppose (-3,5) is a point on the graph of y=g(x),

What point is on the graph of y=g(3x+9)?

The book gives the answer as (-4,5), I'm assuming, by first subtracting 9 from -3 and then multiplying -12 by 1/3 to get the x coordinate. However, given the standard order of operations, I can't figure out why it shouldn't be (-10,5) by first multiplying 1/3 by -3 to get -1 and then subtracting -9 to get the x coordinate.

If anyone can help me understand why, I'd be thankful.