# Math

posted by on .

I need help with this problem:

If N= {1,2,3,4,....}, A= {x/x=2n-1, n E N}, B={x/x=2n, n E N}, and C= {x/x+2n +1, n=0, or n E N}, find the simplest possible expression for each of the following:
a. A U C
b. A U B - the U stands for union
c. A (intersects) I can't find the figure) C
d. A (intersects) B

Also, I used the E as ELEMENT in the top part of the question. Hopefully it isn't too confusing! I am very lost on this problem!

It might help if you gave A,B and C names so you can see what the sets represent. Write out the first 3 or 4 terms if you're not sure, but you should learn to identify properties too.
For A the first three terms are 1,3,5, the first three terms of B are 2,4,6 and the first three are 1,3,5.
You should be able to see that A is the positive odd numbers, B is the positive even numbers and C is also the positive odd numbers.
Since A and C are the same sets, what is the union of them?
Since A and B are the natural separation of the positive integers into odd and even numbers, what is their union?
What is the intersection of a set with itself? You can use int for intersection or just spell it out, I can see what you mean either way
Do A and B have any elements in common?

5t+2=7

You should post a new question when your question is not related to the first one in the thread. That way we won't miss your question.
You posted;
5t+2=7
I'm not sure what the question is, find t?
Subtract 2 from both sides to get
5t=5 then divide both sides by 5.

5t+2=7

5t+2=7

5t=5

t=1