the focus and directrix will both be shifted down 3 units
An alternating series

converges if

is monotonic and

as

. Here

.
Let

. Then

, which is positive for all

, so

is monotonically increasing for

. This would mean

must be a monotonically decreasing sequence over the same interval, and so must

.
Because

is monotonically increasing, but will still always be positive, it follows that

as

.
So,

converges.
(688-684) x 222
You have to do what’s in the parentheses first because of PEMDAS
688-684=4
Then you have to multiply
4x222
=888