1. Suppose A = { 1, 3, 5, 7, 9, 11 , 13} and B = {2, 3, 5, 7, 11, 13}. Find the value of A U B .  2. suppose c: {prime numbers less than or equal to 20}. find n(C)

3. Suppose A = { 2, 3, 4, 5, 6, 7, 9, 12} , B = {2, 12, x, 9} and B is a subset of A. What possible values could x have?

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Problem 1

Explanation:

The notation A U B means we're applying a union between A and B. This will form a larger set in which items from A or B are thrown into A U B. Think of "union" as in getting married, and person A's stuff is combined with person B's stuff to form a larger set. Any duplicates are tossed. It's often helpful to sort from smallest to largest.

Problem 2

Explanation:

Set C is defined as the set of prime numbers less than or equal to 20. The roster form is C = {2,3,5,7,11,13,17,19} which basically lists every item that fits the description earlier. Note how the value 1 is not prime, so it's not in the set C.

From here, we simply count out the values in set C to find there are 8 values. Therefore, n(C) = 8.

Problem 3

Explanation:

Let's consider a real world example of set vs subset. Consider the set of all animals and consider the subset of all dogs. Let's say

A = all animals

B = all dogs

We can see that set A is clearly larger than B. Also, any member of set B is also in set A, but not the other way around. In other words, if something is a dog, then they are also an animal. However, this doesn't work the other way around. For instance, we could have a cat in set A that wouldn't be in set B.

Let's return to the problem at hand. Since B is a subset of A, this must mean everything in B = {2,12,x,9} is found in set A. Sure enough, the 2, 12 and 9 are all in set A. The x must also be a value in set A so we could have

x = 3

x = 4

x = 5

x = 6

x = 7

as our possible answers. I'm not listing x = 2, x = 9 or x = 12 as they have been taken care of. I'm assuming that your teacher wants {2,12,x,9} to list unique items (ie it's after the duplicates are tossed out).

to plot points   for x just start at the origin (middle) and go to the left however many times it say(if the number is a positive) if the number is a negative then go right however many times it says if it is 0 go nowhere

now keep you pencil there and go up however many times it says on y(if it is positive) if it is negative then go down however many times it says. if it says 0 go nowhere.

you have just plotted a point! now when you finish plotting all of them connect them with a ruler

plot each point as (-3, 7), (0,4), (3,1), (8,-4)   in the parenthesis on the left of the comma is x and the right is y.

5 x 14?

im new, sorry if this is wrong.

step-by-step explanation: