How do you do questions like this:

-9y-12=93

I need to know the steps as well.

You want to do things that get y all by itself on the left, so first add 12 to both sides.

-9 y -12 + 12 = 93 + 12
or
- 9 y = 105
now divide by -9 to get y alone
- 9 y / - 9 = 105 / - 9
or
y = -105/9