Evaluating a variable expression

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Discussion Overview

The discussion revolves around evaluating a variable expression involving the variables a, b, and c, specifically the expression 5ab/12 - 2cb. Participants explore how to clarify the expression's structure and how to compute it using given variable values.

Discussion Character

  • Homework-related
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant presents the expression 5ab/12 - 2cb but does not clarify its structure, leading to ambiguity.
  • Another participant points out the potential for misunderstanding and suggests using bracketing symbols to clarify the expression's intended form.
  • There is a reiteration of the two possible interpretations of the expression, emphasizing the importance of clarity in mathematical notation.
  • A participant expresses difficulty in using a calculator and seeks guidance on how to input the expression correctly.
  • Another participant encourages the use of the provided variable values to substitute into the expression rather than relying on a calculator.
  • A participant shares their background, indicating they are new to the subject and requests book recommendations for further learning.
  • Another participant affirms the value of forum feedback over books, suggesting that interaction can enhance understanding.

Areas of Agreement / Disagreement

Participants generally agree on the need for clarity in mathematical expressions and the importance of substituting variable values. However, there is no consensus on the best method for learning, as some advocate for books while others prefer interactive forum assistance.

Contextual Notes

Participants express varying levels of familiarity with mathematical notation and calculator use, indicating a range of experience and comfort with the subject matter.

Who May Find This Useful

This discussion may be useful for individuals new to algebra or those seeking clarification on evaluating expressions with variables, as well as those looking for community support in learning mathematics.

rodgerst414
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a=4,b=3 and c=-2

5ab/12-2cb:confused:
 
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As posted, it is hard to tell if you mean:

$\displaystyle \frac{5ab}{12}-2cb$

or

$\displaystyle \frac{5ab}{12-2cb}$

Until you learn to use $\LaTeX$, I recommend you use bracketing symbols to make it clear exactly what the denominator is.

If the first choice above is what you intend, then you could type (5ab/12) - 2cb, and if the second choice is what you intend, then you could type (5ab)/(12 - 2cb).

Do you see how that removes the potential ambiguity?
 
MarkFL said:
As posted, it is hard to tell if you mean:

$\displaystyle \frac{5ab}{12}-2cb$

or

$\displaystyle \frac{5ab}{12-2cb}$

Until you learn to use $\LaTeX$, I recommend you use bracketing symbols to make it clear exactly what the denominator is.

If the first choice above is what you intend, then you could type (5ab/12) - 2cb, and if the second choice is what you intend, then you could type (5ab)/(12 - 2cb).

Do you see how that removes the potential ambiguity?
it is the first one i just don't know how to put them in the calculator or write them on here.
 
Okay, you have technically written it correctly then, but there are so many students who would write what you did when they mean the second choice, that it is best to make sure.

Now, given what I told you in your first topic, what do you think you need to do here as the first step?
 
rodgerst414 said:
it is the first one i just don't know how to put them in the calculator or write them on here.
It is the first on you wrote how do you put into a calculator.
 
MarkFL said:
Okay, you have technically written it correctly then, but there are so many students who would write what you did when they mean the second choice, that it is best to make sure.

Now, given what I told you in your first topic, what do you think you need to do here as the first step?
Sorry but this is my first time to do these problems i don't understand.I quit school at a younger age. i am 41 first time in college.This is this the class they put me in.Can you recommend some books for me to learn these kinds of problems.
 
We really don't need a calculator for this. What we want to do is use the values we are given for the variables and plug them into the expression. Can you write the expression with the numbers put into replace the variables?
 
rodgerst414 said:
...Can you recommend some books for me to learn these kinds of problems.

I think you have made a great start...you have come to a wonderful forum to get help, and I think once you get the hang of the procedure for these, you will understand what you need to do for other similar problems.

Books are good, but the feedback you get from helpers on a forum is much better.(Yes)
 

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