Expand -5/6 [9b-12]

Expanding -5/6 [9b-12] involves distributing -5/6 to both terms within the brackets:

-5/6 [9b-12] = (-5/6)(9b) + (-5/6)(-12)

This simplifies to:

-45/6b + 60/6

Which can be further simplified to:

(-45b + 60)/6

or

-15/2b + 10