Question

Find B D.
B: {−2, −1, 1, 4, 7, 12}
D: {numbers divisible by 3 from 1 to 15}

{12}

{−2, −1, 1, 3, 4, 7, 12}

{−2, −1, 1, 3, 4, 6, 7, 9, 12, 15}

{ }

Answer 1

Is there another symbol between B and D?

Answer 2

U

Answer 3

The U is the union, which is the combination of all the values in B and D.
Since we already know the numbers in B, what numbers are in D? (Which numbers from 1 to 15 are divisible by 3)

Answer 4

When you find the values in D, then combine them with what's in B to get your answer

Answer 5

{12}

Answer 6

12 isn't the only number from 1 to 15 divisible by 3, though

Answer 7

so you are looking for the union of the 2 sets

First find the elements of set D

Set D = { 3, 6, 9, 12, 15}

you need all the elements of set C and D any elements common to both are any recorded once.

Answer 8

I really don't get it

Answer 9

Do you understand how we got the numbers in set D?

Answer 10

Yes I do I just don't get how its not 12

Answer 11

Because you also need to include the other numbers in D as well as the numbers in B

Answer 12

So what other numbers can be in D?

Answer 13

the second one

Answer 14

The answer choices don't mean anything yet. Can you think of any numbers besides 12 that are divisible by 3 and from 1 to 15?

Answer 15

1,6,

Answer 16

1 isn't divisible by 3, so that can't be one of our numbers

Answer 17

then it doesn't have a number it thats the case the answer would be {}

Answer 18

No. Okay, for set D, we need to find all the numbers that can be divided by 3 and are from 1 to 15. Those are 3, 6, 9, 12, and 15. So set D is {3, 6, 9, 12, 15}
If we add that to set B, we get:
{−2, −1, 1, 3, 4, 6, 7, 9, 12, 12, 15}
We need to take out one 12 since a union only lists each number once.
So what's the final answer?

Answer 19

The final answer would be b

Answer 20

No. Answer 2 is missing 6, 9, and 15 from set D.

Answer 21

I Meant C

Answer 22

That's correct :)

Answer 23

Thank You so much :)

Answer 24

You're welcome ^_^