MHB Evaluating a variable expression

AI Thread Summary
The discussion focuses on evaluating the expression 5ab/12 - 2cb using the values a=4, b=3, and c=-2. There is an emphasis on clarifying the expression's format to avoid ambiguity, particularly in distinguishing between two possible interpretations. The importance of using bracketing symbols for clarity is highlighted, especially for beginners. A participant expresses their struggle with the material, mentioning their late return to education and seeking recommendations for learning resources. Overall, the conversation encourages engagement with the forum for assistance and emphasizes the value of community support in learning.
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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