Simplify using DeMorgan's theorem. (Digital Logic) (Electronic class)?

[Cornflakes]

Hi there
I have 2 question

1- Simplify the output Z using DeMorgan's theorm

Z=[(AB)'+(A+B)']'

My attempt was:

(AB)'= A'+B'
(A+B)'= A'B"

Then
A'+B'+A'B'

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2-
What is the logic output Z in
Z=[(AB)'+(A+B)']'
if A=1 and B=0


Thank you