Question

Find A ∩ B if A = {3, 6, 9, 12} and B = {2, 4, 6, 8, 10, 12}.
Ø
{6, 12}
{2, 3, 4, 6, 8, 9, 10, 12}

What is the solution set of {x | x < -3} ∩ {x | x > 5}?
all numbers except -3 and 5
the numbers between -3 and 5
the empty set
all real numbers

What is the solution set of {x | x < 2} u {x | x ≥ 2}?
all numbers less than -2 and greater than 2
the numbers between -2 and 2
the empty set
all real numbers

Answer 1

A ∩ B means the elements should be in BOTH sets.
Take each element from set A and see if it is in set B. If it is, include it. Otherwise discard it.

Answer 2

so then it would be B?

Answer 3

Yes, {6, 12}

Answer 4

for #1

Answer 5

I think I understand it THANK YOU!!!

Answer 6

what about the next 2 tho how would I do those?

Answer 7

You are welcome.

For the second one draw a number line and see if they share any numbers.
The first one is x < -3. That means all numbers to the left of -3 on the number line.
The second one is x > 5. That means all numbers to the right of 5 on the number line.

Do they share any numbers?

Answer 8

sorry computer froze doing it now

Answer 9

te 2nd one no

Answer 10

They don't share any numbers. So the "intersection" or "common elements" is nothing or an empty set.

Answer 11

ok and the 3rd they do shar a number so would that be all real numbers?

Answer 12

The third one is: {x | x < 2} u {x | x ≥ 2}?

The first one, x < 2, includes all numbers to the left of 2.
The second one, x ≥ 2, includes all numbers to the right of 2, including the number 2.

The UNION of these two, includes ALL numbers and so the the answer is: all real numbers.

PS: In the third one we are doing union and not intersection. In intersection you look for items/numbers that are common. In union you combine the items/numbers.

Answer 13

ok but what is union im sorry for all the questions I was out of school for a tear after my baby girl was born so im trying to catch up for my GED test tomorrow

Answer 14

Union is like addition.

If A = { 10, 12, 15} and B = { 8, 15, 23 }

then A U B = { 8, 10, 12, 15, 23 } ("union" implies combining both sets)
A ∩ B = { 15 } ("intersection" implies common items present in both sets)

Answer 15

ok so if I see n think intersection and U think Union right?

Answer 16

Yes.

Answer 17

Ok thanks you been suck a big help!!

Answer 18

*such

Answer 19

Traffic lights are at the intersection of roads. The lights are shared by BOTH roads. So intersection is shared.
Union, is combined with duplicates removed.

Answer 20

A = { orange, blue, yellow } B = { purple, blue, red }

What is A ∩ B ?
What is A U B ?

Answer 21

n is blue?

Answer 22

correct.

Answer 23

and im going off the example you gave me U is AUB={Blue, orange, yellow, purple, red}

Answer 24

correct.
I think you got it!

Answer 25

Do well in your GED.

Answer 26

Thanks!

Answer 27

You are welcome.