Math Is Fun Forum

Mister_Scary

Member

Registered: 2010-10-22

Posts: 30

Help with 5th question please???

Solve the equation 7x - 8a = 3x + 24a for x.

A. x = 3a

B. x = 8a

C. x = 24a

D. x = 32a

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Help with 5th question please???

Hi;

7x - 8a = 3x + 24a

Same as the others, just looks tougher.  You want the x all by itself on one side. Add 8a to both sides.

      7x - 8a = 3x + 24a
          + 8a        +   8a          -8a + 8a cancel each so that = 0
------------------------------          24a  + 8a = 32a, just bring down the rest.
      7x + 0 = 3x + 32 a

7x = 3x + 32 a

What would you do next?

---

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 5th 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 5th 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.

I will do a little bit more of the problem for you, hopefully you will try something.

This is where I left off:

7x = 3x + 32 a

We still want to get the x by itself on one side. That is all there is to these. You can do it. Anybody can!

We subtract 3x from both sides.

7x = 3x + 32 a
-3x   -3x
---------------------
4x = 32 a

Okay you are only 1 step away. All 6 of your problems are similar. You need to get that 4 out of there.
It is connected to the x by multiplication. Try dividing by 4, on both sides remember.
Please try something, you have not done any work on any of the six problems.
These are homework, you must at least try!

---

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 5th question please???

I came up with X = 8a for this one.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Help with 5th question please???

Hi;

How are you arriving at your answers. Just tell how you think about them. I will put you on the right track.

We are here:

4x = 32 a

---

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 5th question please???

7 x 8a = 56a
56a - 8a = 48a
which is equal to
3 x 8a = 24a + 24a = 48a

So x = 8a

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Help with 5th question please???

Hi Mister_Scary;

You can manipulate somewhat but I cannot make heads or tails about that. In short you lost me.

Please focus on the simpler way, just for now. We are here.

4x = 32 a     We need to get x by itself. We divide both sides by 4.

4x = 32 a
-------------
     4

we get for the left.

Now what does that equal?

---

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.