Homework help question: 2x-1/1-2x = -1 why?

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Homework Help Overview

The discussion revolves around the equation (2x - 1)/(1 - 2x) and its equivalence to -1. Participants are seeking clarification on the algebraic manipulation and interpretation of the expression.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants are attempting to understand the reasoning behind the equation equating to -1. Some are questioning the clarity of the original expression and suggesting the use of parentheses for proper interpretation.

Discussion Status

The discussion is active, with participants providing insights into the algebra involved. Some guidance has been offered regarding the interpretation of the expression, but there is no explicit consensus on the initial confusion regarding the notation.

Contextual Notes

There is an emphasis on the importance of notation and clarity in mathematical expressions, as well as the potential for misinterpretation without proper use of parentheses.

xsgx
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Why does 2x-1/1-2x equal negative one?Can someone explain this to me because i don't get it.
 
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xsgx said:
Why does 2x-1/1-2x equal negative one?Can someone explain this to me because i don't get it.

Because -1 * (2x-1) = -2x+1 = (1-2x)

Does that help?
 
xsgx said:
Why does 2x-1/1-2x equal negative one?Can someone explain this to me because i don't get it.
This probably doesn't mean what you actually wrote, but it turns out to be equal to -1 anyway. Here's what you wrote:
$$2x - \frac{1}{1} - 2x = 2x - 1 - 2x = -1$$

If you want what you write to be interpreted the way you mean it, use parentheses, as in (2x - 1)/(1 - 2x).
 
Mark44 said:
This probably doesn't mean what you actually wrote, but it turns out to be equal to -1 anyway. Here's what you wrote:
$$2x - \frac{1}{1} - 2x = 2x - 1 - 2x = -1$$

Hah! Good eye! :smile:
 
Mark44 said:
This probably doesn't mean what you actually wrote, but it turns out to be equal to -1 anyway. Here's what you wrote:
$$2x - \frac{1}{1} - 2x = 2x - 1 - 2x = -1$$

If you want what you write to be interpreted the way you mean it, use parentheses, as in (2x - 1)/(1 - 2x).

Yeah i meant (2x-1)/(1-2x)
 
berkeman said:
Because -1 * (2x-1) = -2x+1 = (1-2x)

Does that help?

Yeah that helps.Thank you.
 

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