Question

Someone please help me step by step i've been stuck on this and i want to learn

1. D = p(3 + nr) solve for r

Answer 1

@milli_lovesyouu begin by dividing both sides by p.

Answer 2

D/p = (3+nr) ?

Answer 3

Very good. Now 3 + nr isn't being multiplied by anything anymore so the parentheses are no longer needed. You can remove them.

Answer 4

okay so then i have to get rid of the n right?

Answer 5

The next step after removing the parentheses is to subtract 3 from both sides.

Answer 6

-3d/p = nr ?

Answer 7

The right side is correct, but the left side is incorrect. You wrote -3 as multiplying d/p, but what you actually what to do is subtract 3 from d/p. Have an idea of how to write that?

Answer 8

no idea :(

Answer 9

How do you write six minus 3?

Answer 10

6 - 3

Answer 11

3 - d/p ?

Answer 12

How do you write one-third minus 3?

Answer 13

Very good. How do you write d/p minus three?

Answer 14

d/p - 3 = nr?

Answer 15

Yes, correct. Subtracting 3 from d/p means the same as d/p minus three. You should pay very close attention to the way math phrases are worded. Now the last step is important and I want you to get it right. First I want you to place everything on the left side in parentheses.

Answer 16

no idea im sorry i tried on paper but it didnt make sense to me

Answer 17

Type it first in here. I'll explain it later. Just simply place the expression on the left side within a set of parentheses.

Answer 18

d/p is outside the ( ) right ?

Answer 19

The entire expression on the left side, put parentheses around it.

Answer 20

(d/p - 3) = nr
then, multiple both sides by n?

Answer 21

The expression above is correct as written. Notice that n is being multiplied by r. So to undo that, we have to actually perform an inverse operation. DIVISION. Divide both sides by n.

Answer 22

The final expression is going to look kind of awkward, I know, but no one says the equations have to look pretty.

Answer 23

You're changing it to something else. When you put the expression in parentheses, YOU CANNOT alter it. It's ONE expression. You divide the entire expression by n.

Answer 24

okay, so it'll be (d/p - 3) / n = r ?

Answer 25

Exactly correct.

Answer 26

And if you're confused about how that looks on paper, it will look like this:

\(\dfrac{\dfrac{d}{p} - 3}{n} = r\)

Answer 27

thats my answer?

Answer 28

Yes

Answer 29

these are my answer choices though ?

Answer 30

@Hero

Answer 31

It's unfortunate that they have done that, because now they basically want you to re-write it in a different form.

Answer 32

can you help me? :( please

Answer 33

No wonder you were confused about how to write the final form.

Answer 34

yea i was looking at my book and other examples but i couldn't figure it out for nothing

Answer 35

It will be more difficult to explain based on the manipulation necessary to re-write it in the proper form.

Answer 36

its okay ill just email my teacher about it i guess

Answer 37

Thank you so much for all your help!

Answer 38

Why do you need to email your teacher about it? Have you given up on solving this?

Answer 39

what other way can i write this?

Answer 40

i was looking at answer choice a at first

Answer 41

The next step is to first re-write it this way:
\(\dfrac{1}{n}\left(\dfrac{d}{p} - 3\right) = r\)

Believe it or not, the expression on the left is equivalent to the expression we got for our initial answer.

Answer 42

Next, you distribute \(\dfrac{1}{n}\) over \(\dfrac{d}{p} - 3\) to get \(\dfrac{d}{pn} - \dfrac{3}{n}\)

Answer 43

Afterwards multiply \(\dfrac{3}{n}\) by \(\dfrac{p}{p}\) to get \(\dfrac{3p}{p}\)

So the expression on the left now looks like
\(\dfrac{d}{pn} - \dfrac{3p}{pn}\

Answer 44

Notice the denominators are the same so we can combine the expression to get:
\(\dfrac{d - 3p}{pn} = r\)

Answer 45

So, A right?

Answer 46

A is correct but the important thing to know is how to get A. You can't get it by eyeballing it and you should never try to guess with problems like these.

Answer 47

yea, i like explanations so i learn because these problems are on my next test :( im in college intermediate Algebra

Answer 48

Thank you so much!!!!