Question

can someone please help me with this solution. write the solution of this inequality in set-builder notation 7-3d greater than or equal to 28

Answer 1

@precious13 Do you know the solution and just want help for set builder notation?

Answer 2

yes @Directrix

Answer 3

@precious13 Post what the solution is so that we can write it in set builder notation.

Answer 4

You need to get the solution before worrying about the set builder notation.

7-3d greater than or equal to 28

7 - 3d ≥ 28 -----> Add -7 to both sides
-7 -7
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-3d ≥ 21 ----> Divide both sides by (-3) and post what you get when you
return online. @precious13

Answer 5

ok thanks @Directrix

Answer 6

How about staying online long enough for us to finish this? Okay? If you will do that, I will help you finish it. Just lemme know.

Answer 7

sure

Answer 8

Now, this is tricky:

-3d ≥ 21

When you divide an inequality by a negative number, the order (direction) of the inequality symbol is reversed.

Answer 9

-3d ≥ 21 -----> Divide by (-3)

d ≤ -7 ---> So this is the solution. All numbers less that -7 and equal to -7 make 7 - 3d ≥ 28 a true statement.

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Don't leave. We have to do set builder notation.

Answer 10

This ---> d ≤ -7 is what we are going to write in set builder notation.

Answer 11

You can read about set builder notation after this illustration.

d ≤ -7


{d | d is a real number and d ≤ -7} --> this is it

Read as: The set of all d such that d is a real number AND d is less than or equal to 7.

@precious13 (I don't know where you are in your studies - your teacher may not require the "is a real number" blurb.)

Answer 12

Question?

Answer 13

no but thanks for your help

Answer 14

You are welcome.