9. The formula ?x((C(x) ? F(x)) ? Y (x)) represents sentence: Some blue flowers are yellow in a domain X 6= ?

JUSTIFY: y n

10. For any predicates A(x), B(x), the formula ((?xA(x) ? ?xB(x)) ? ?x(A(x) ? B(x))) is a predicate tautology

JUSTIFY: y n

11. ?xA(x) ? ?xA(x) is a predicate tautology.

JUSTIFY: y n

12. For predicate formulas A(x), B(x), ¬?x(A(x) ? B(x)) ? (¬?xA(x) ? ?x¬B(x))

JUSTIFY: y n

13. ?x(A(x) ? A(x)) is a predicate tautology

JUSTIFY: y n

14. For predicate formulas A(x), B(x), ?x(A(x) ? B(x)) ? (?xA(x) ? ?xB(x))

JUSTIFY: y n

15. ?x ? R(x 2 < 0) ? ?x ? R(x 2 < 0) is a true mathematical statement

JUSTIFY: y n

16. ?x2<0(x + 1 = 4) ? ?x2<0(x + 1 = 4) is a true mathematical statement in the set R of real numbers

JUSTIFY: y n

17. ¬?n?x(x < 1+n n+1 ) ? ?n?x(x ? 1+n n?1 ))

JUSTIFY: y n

and also the following in the picture

- Attachment 1
- Attachment 2
- Attachment 3

18 Ity SO for I VEN is a ( mathematical ) predicate with the domain NJUSTIFY319 . For predicate formulas A ( x ) . B ( x )( IP ( A ( I ) UB ( 2 0 ) ) = ( 324 ( 2 ) LAB ( 2 )JUSTIFY320 VIER ( 2 2 0 ) – JERI1 )is a true mathematical statementJUSTIFY3