Postulates (also called axioms) are used to determine what you're talking about, and, by means of logic, what you can say about what you're taking about.
Number 8:
A theorem is a statement that needs to be proven in order to be considered true using previously proven theorems and axioms (statements that are considered true without the need of proof).
Answers & Comments
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Number 5:
Number 6:
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Therefore the answer:
5. A
6. B
7. B
8. A
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Number 7:
Number 8:
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