Answer:
(a) 1st, 2nd
(b) 4th
Explanation:
(a) Option 1: Expanding with the distributive property, we have

which is equivalent.
Option 2: Multiplying the terms gives
,
which is equivalent.
Option 3: We don't know what x is, so there is no way to write
as
. This is not equivalent.
Option 4: Expanding with the distributive property gives

which is not equivalent.
(b) First, we combine like terms in the given expression:

Looking at the given answer choices, only the fourth option is equivalent.