I need to add a horizontal compression by a factor of 1/4, then a reflection in the y-axis, followed by 2 units down.

Original equation is y = 3x - 6

I understand how to do expansions, compressions, translations, etc, but I don't understand how to add a horizontal compression of 1/4 when the original equation already shows a horizontal compression of 1/3. Do I multiply them together to get a horizontal compression of 1/12?

I am also wondering what would happen if the original equation was y = 1/3x - 6. How do I add a horizontal compression to an equation that already has a horizontal expansion?

Thanks very much for any help.