Math Is Fun Forum

Mister_Scary

Member

Registered: 2010-10-22

Posts: 30

Help with 2nd question please???

If the perimeter of a rectangle is expressed by the formula p = 2L + 2w, the side w can be found by the formula:

A.....p - 1
w = ------
........2

B. w = p - 2L

C.....p - 2L
w = -------
........2

D. w = p - a

*The dots are so everything lines up to look like a fraction.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Help with 2nd question please???

Hi;

You start with P = 2L + 2W and manipulate until you get the W all by itself on the left hand side like the P is right now.

Reverse it.

2L + 2W = P

Subtract 2L from both sides.

2W = P - 2L

Can finish up now? Try it. See if you can.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Mister_Scary

Member

Registered: 2010-10-22

Posts: 30

Re: Help with 2nd question please???

Well thanks for the answer on the first question. I'll keep posting the other five around the internet until I can get them answered.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Help with 2nd question please???

I'll keep posting the other five around the internet until I can get them answered.

You are just one tiny step away from doing it yourself.
Then you would be able to do 1 to 100000000000000 questions by yourself.
I have shown you how to essentially do that on your own. Have you no desire to learn math for yourself?

Now come on, you just have to get rid of that 2 on the left and you are done. How do you undo multiplication?

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Mister_Scary

Member

Registered: 2010-10-22

Posts: 30

Re: Help with 2nd question please???

Okay.......... I've been up all night working on these so here goes.

I have w = p - 2L for this one.

Last edited by Mister_Scary (2010-10-22 21:22:49)

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Help with 2nd question please???

Hi Mister_Scary;

Yes, I see what you did and like it. You guessed at B. That is fine gamemanship, never leave an answer blank. But unfortunately that answer as a guess is wrong.

Here is what you are left with:

2W = P - 2L

You need to get the W by itself. That 2 has got to go. It is connected to that W by multiplication.
To get rid of it we divide by 2. What do you get when you divide both sides by 2.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Mister_Scary

Member

Registered: 2010-10-22

Posts: 30

Re: Help with 2nd question please???

You've got to be kidding me!

Okay...."C" looks like it's being divided by 2.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Help with 2nd question please???

You've got to be kidding me!

Heck no!

You are still guessing at the answers here is what you should do:

We divide both sides by 2:

2W = P - 2L
----------------
      2

Now what happens when 2W is divided by 2? You have

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Mister_Scary

Member

Registered: 2010-10-22

Posts: 30

Re: Help with 2nd question please???

No, and that's why I came here. But now I see that I'm just going to have to get the answers to questions 2, 3 and 6 wrong on this stupid test I have to take.

Thank you for your time and effort.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Help with 2nd question please???

Hold it maybe I can make it easier for both of us. You are trying to understand this.

You can cancel things that are the same on top and bottom. Like this.

Now you are left with just the w.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Mister_Scary

Member

Registered: 2010-10-22

Posts: 30

Re: Help with 2nd question please???

Yep.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Help with 2nd question please???

So we have the W by itself. What do we have on the right?

We started with this:

So we have:

Does that look familiar to you?

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Mister_Scary

Member

Registered: 2010-10-22

Posts: 30

Re: Help with 2nd question please???

Yes, that was my guess from several posts ago.:D

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Help with 2nd question please???

Yes it was. I showed you another method that you could do in your sleep, It is a rote procedure that works for all of them. You do not even have to do any thinking just follow the rules. I know it seems foreign now but you learned something whether you know that or not. This method is the one your teacher wants, this is the one that scores the points.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.