Stuck!

[omink123]

So I am in algebra 1 and we are having a big test tomorrow. One thing I need help on is "finding x" or transforming simple equations....especially ones with fractions...here is an example.


8-2/3(x-4)=-4

PLEASE HELP!!

 

[tkhunny]

Is that \(\displaystyle 8 - \frac{2}{3}(x-4) = -4\)? If so, this is not what you hae written. Remember the Order of Operations and how to use prentheses.

Multiply the whole thing by 3 and see if that helps. Then ponder why I woud do that.

 

[jsterkel]

There are two things to keep in mind.

1) combine "like" terms. In this case, we can try to combine the "8" and the "-4". They are "like" each other, because niether is multiplied by x.

2) Its an equation, so we have to keep both sides equal. So if we subtract 8 from the left, we should subtract 8 from the right.

I think your problem is 8 - 2/(3(x-4)) = -4

So, lets combine the 8 and the -4. We do this by subtracting 8 FROM BOTH SIDES.

8 - 8 -2/(3(x-4)) = -4 -8

0 - 2/(3(x-4)) = -12

-2/(3(x-4)) = -12

Now lets start to simplify the (3(x-4)) portion. We multiply the 3 by both terms, so we get 3*x - 3*4, or 3x-12.

So now we have

-2/(3x-12) = -12

I don't like negative numbers, so lets multiply both sides by -1. This will turn both sides positive.

-1*-2/(3x-12) = -12 * -1

2/(3x - 12) = 12

Now, we have the x as a denominator, so lets multiply both sides by (3x - 12)

(3x-12) * 2/(3x-12) = 12 * (3x-12)

On the left, we can rearrange this to be 2*(3x-12)/(3x-12) = 2*1 = 2

So we have
2 = 12 * (3x-12)

This " 12 * (3x-12) is similar to what we did above. We can multiply 12 by both terms.

2 = 36x - 144

Again, we need to combine like terms, this time by adding 144 to both sides.

2 + 144 = 36x -144 + 144
146 = 36x + 0
146 = 36x

Now, lets divide both sides by 36.

146/36 = 36x/36

146/36 = x

We can switch it around, because we normally read it that direction, and simplify the fraction a bit.

x = 146/36
x = 73/18


I hope this helps.

 

[lookagain]

I hope this helps.

jsterkel,

you did not "help."

You did *all* of it for the student.

 

[lookagain]

Good stuff, jsterkel.
If you do more than indicated by Forum guidelines,
a \(\displaystyle --->\) MODERATOR \(\displaystyle <--\)may advise you.

Yelling (text in all caps) is discouraged on this forum.

And, no, it is not "good stuff," jsterkel as I pointed out in a previous
post above. Actually, I'm shocked that that was typed.

In any event, this is a *help* forum, not a "do-your-homework-for-you-forum."
I appreciate your understanding in this.

I wouldn't want you to get the wrong idea in mixed messages.

I'll be happy to advance this message to the administrator to set
things right again.

Thanks, jsterkel.

 

[jsterkel]

Moderators, If I did too much, please let me know.

In my opinion, I showed the process of working one problem that may or may not have been homework (TKHunny read the same equation and got an entirely different problem, one that has a simpler solution).

My statement was that in my opinion, the student needed to see a detailed example.

I hope that my detailed example helps the student grasp the concepts.

Next time, I will use an example problem of my own, rather than an example posted by the student.