Evaluating with fractions

C

collette

New member
Joined
Jul 29, 2005
Messages
2
Hello,
I am trying to help my daughter with homework, I've never had algebra, so I just do the best. I realize this is an easy problem, and I think I am just making it hard and confusing myself. The problem is:
3x
---
5y
for x = 1/5 and y = -1/2

I think I should reduce it to 16/5 * -2/11 getting -32/55, but that just doesn't seem right.
Any help is appreciated.

Thank you!
Collette
 
You have:

. . . . .(3x)/(5y)

You are evaluating at x = 1/5 and y = -1/2. Then:

. . . . .[3(1/5)] / [5(-1/2)] = [(3/1)(1/5)] / [(5/1)(-1/2)] = [3/5] / [-5/2] = [3/5][-2/5] = -6/25

I have no idea how you got the values 16/5 and -2/11...?

Eliz.
 
Hello,
Thanks for the reply.
Well, like I said, I don't really know what I'm doing. I'll do my best to explain how I came up with my numbers. Using the examples in the book, I thought I needed to reduce the 3 1/5 and 5 -1/2 to fractions, hence the 16/5 and the -11/2. In the book it shows that the -11/2 is reciprocal and should be flipped, then both fractions multiplied. I had no problems figuring out the expressions that contained only fractions, and was able to check my answer with the given answers in the book, but there were no examples using whole numbers and fractions for me to compare with. I guess I just wasn't getting the idea of reducing, but using your example I understand now. I really appreciate your help! :)
Thanks again!
Collette
 
The expressions (as posted) are 3x and 5y, not 3 + x and 5 + y. You are multiplying, not adding.

Eliz.
 
Collette, remember this:
(a/b) / (c/d) = (a/b) * (d/c)
In other words, "bring up" the lower fraction in order to multiply, but INVERT it;
example (3 / 5) / (4 / 7) = (3/5) * (7/4) = 12/35

AND: when you see something like "5a", that means 5 times a;
so if a = 7, then 5a = 5 * 7 = 35; tu comprends?
 
Babel Fish Translation
In English:
you include/understand
Translate again - Enter up to 150 words
tu comprends
Use the World Keyboard to enter accented or Cyrillic characters.

Hmmm...me not know wat you mean, ma belle Eliz: see above.

"Tu comprends" is pure correct French, TK:
Je comprend
Tu comprends
Il comprend
Now why the "s" if "tu" is beyond me...

Tell ya'll one thing: I was sure happy to switch from French
to English from primary to high school.
 
OH MY GOD!!!
"tu comprends?" is french, meaning"do you undersatand?"

and "tu comprendesis Spanish. ALRIGHT!!

god.
seems like im talking to a whole bunch of idiots.
 
beautifull_love101 said:
god.
seems like im talking to a whole bunch of idiots.
Click to expand...
Um... no, we aren't the ones who are looking like idiots right now. :roll:

Eliz.
 
im not trying to offend anyone. im just trying to conclude about the whole argument.
 
beautifull_love101 said:
im not trying to offend anyone....
Click to expand...
Then kindly stop calling people idiots.

In addition, it probably wouldn't hurt if you learned how to spell, how to punctuate, and how to use proper grammar. And it would likely be appreciated if you would kindly refrain from presuming to correct others, at least until you know what you're talking about.

Thank you for your consideration.

Eliz.
 
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