So is 3xy

That's right

That doesn’t mean 3xy2 is 9y2x2.

That's right. It means 3abb=(3xaxbxb)

The power only applies to the last element

Factor yes, hence the special rule about Brackets and Exponents that only applies in that context

like how (8)22 only squares the 2

It doesn't do anything, being an invalid syntax to follow brackets immediately with a number. You can do ab, a(b), but not (a)b

not (6ab)(6ab)(6ab)

Yep, as opposed to 6(a+b), which is (6a+6b)

3(x+1)2 for x=-2 is 3, not 9

No it isn't. See previous point. Do we have an a(b+c), yes we do. Do we have an a(bc)²? No we don't.

2(x-b)2 has a 2b2 term

No, it has a a(b-c) term, squared

shut the fuck up

says someone still trying to make the special case of Exponents and Brackets apply to a Factorised Term when it doesn't. 😂 I'll take that as your admission of being wrong about a(b+c)=ax(b+c) then. Thanks for playing

For a=8, b=1, that’s 2*(81)(8*1).

Only if you had defined it as such to begin with, otherwise the Brackets Exponents rule doesn't apply if you started out with 2(8)², which is different to 2(8²) and 2(ab)²

..and there's still no exponent in a(b+c) anyway, Mr. False Equivalence