How to Write These Elements of Sets?

[AhAlhaimi]

Hi everyone,

Please take a look at the picture, how can I solve this?

 

[tkhunny]

What does "(2|x)" mean? State it, please.

 

[AhAlhaimi]

What does "(2|x)" mean? State it, please.

2 divides by x

 

[tkhunny]

2 divides by x

Not quite. Just "2 divides x".

Okay, 2|2?
2|3?
2|4?
etc.
Find all of them. Move on to the next statement.

3|2?
3|3?
etc.

Having done all that, what does [math]\land[/math] mean?

 

[AhAlhaimi]

Not quite. Just "2 divides x".

Okay, 2|2?
2|3?
2|4?
etc.
Find all of them. Move on to the next statement.

3|2?
3|3?
etc.

Having done all that, what does [math]\land[/math] mean?

It means ( And )

 

[tkhunny]

It means ( And )

Well, that's hardly the only thing I asked.

 

[pka]

Hi everyone,

Please take a look at the picture, how can I solve this? View attachment 14063

I fully intend to start an argument with this answer.
The answer to part (c) is \(\displaystyle C=\{2,~3,~4,~6,~8,~9\} \)

I await replies.

 

[AhAlhaimi]

Well, that's hardly the only thing I asked.

Thanks I got A,B. But how can I solve “C

 

[AhAlhaimi]

I fully intend to start an argument with this answer.
The answer to part (c) is \(\displaystyle C=\{2,~3,~4,~6,~8,~9\} \)

I await replies.

Could you please explain that a bit.

 

[Dr.Peterson]

I agree with you. No argument from me.

And if this is a course in logic (or discrete math), that would be exactly the point of the question. How I wish I could see the context of questions like this, to be sure what is being tested. But this doesn't look like a question from a basic algebra course.

So the next question to ask is, When is an "if ... then" statement true?

 

[Steven G]

No argument from me either as I agree with your answer too

 

[HallsofIvy]

AhAlhaimi, pka's point, and of everyone who agreed with him, is that the statement "if A then B" is true if both A and B are true or if A is false (and then it doesn't matter whether B is true or not). Both A= "x is odd" and B= "3 divides x" are true for x= 3 and x= 9 but "x is odd" is false for 2, 4, 6, and 8. If the statement were "x is odd and 3|x" then the answer would be {3, 9}.