Solving Equations with Subtraction: Can You Help Me?

  • Context: High School 
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Discussion Overview

The discussion revolves around simplifying the expression 2x + 1 - ((2x + 3)/2). Participants engage in clarifying the distinction between expressions and equations, and they explore various methods for simplifying the given expression.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants emphasize that the given problem is an expression, not an equation, and thus cannot be solved in the same way as an equation.
  • One participant suggests simplifying the expression by finding a common denominator for the fractions involved.
  • Another participant points out that multiplying parts of the expression incorrectly leads to confusion and incorrect results.
  • Several participants provide different methods for simplifying the expression, with one showing a step-by-step approach leading to (2x - 1)/2.
  • There is a correction regarding the multiplication of (2x + 3)/2, clarifying that it simplifies to 2x + 3, not 4x + 6.

Areas of Agreement / Disagreement

Participants generally agree that the original problem is an expression rather than an equation. However, there are competing views on the methods for simplification and the implications of treating it as an equation.

Contextual Notes

Some participants express uncertainty about the steps involved in simplification and the importance of understanding the distinction between expressions and equations. There are unresolved mathematical steps and varying interpretations of how to manipulate the expression.

Who May Find This Useful

This discussion may be useful for individuals seeking to understand the simplification of algebraic expressions and the differences between expressions and equations in mathematical contexts.

xeon123
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Hi,

I would like to solve this equation but I can't do it.

2x+1-((2x+3)/2)

Can you help me?

Thanks,
 
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xeon123 said:
2x+1-((2x+3)/2)
First simplify the stuff in the parentheses: carry out the division.

(Those are expressions, not equations. No equals sign!)
 
This expression is the same as the following 2x+1-4x-6?

I've multiplied ((2x+3)/2) by 2, and removed the parenthesis.
 
xeon123 said:
This expression is the same as the following 2x+1-4x-6?
No.
I've multiplied ((2x+3)/2) by 2, and removed the parenthesis.
If you had an equation, you could multiply both sides by 2. But here you just have an expression. Divide by 2.

If you really mean to subtract two equations, please show those equations.
 
xeon123 said:
This expression is the same as the following 2x+1-4x-6?

I've multiplied ((2x+3)/2) by 2, and removed the parenthesis.
No, you can't just multiply by 2 and get the same result- and you surely can't multiply just part of an expression and expect to get any thing sensible. And, by the way, multiplying (2x+3)/2 by 2 would just cancel the 2 in the denominator to give 2x+ 3, not 4x+ 6.

You could write the first part as [itex](2/2)(2x+ 1)= (4x+2)/2[/tex] so you can add the fractions (remember getting a "common denominator" so you can add?):<br /> [tex]\frac{4x+2}{2}- \frac{2x+3}{2}= \frac{4x+ 2- 2x- 3}{2}= \frac{2x- 1}{2}[/tex][/itex]
 
Fixed (?) LaTeX.
HallsofIvy said:
No, you can't just multiply by 2 and get the same result- and you surely can't multiply just part of an expression and expect to get any thing sensible. And, by the way, multiplying (2x+3)/2 by 2 would just cancel the 2 in the denominator to give 2x+ 3, not 4x+ 6.

You could write the first part as [itex](2/2)(2x+ 1)= (4x+2)/2[/itex] so you can add the fractions (remember getting a "common denominator" so you can add?):
[tex]\frac{4x+2}{2}- \frac{2x+3}{2}= \frac{4x+ 2- 2x- 3}{2}= \frac{2x- 1}{2}[/tex]
 
xeon123 said:
Hi,

I would like to solve this equation but I can't do it.

2x+1-((2x+3)/2)
As already noted, this is not an equation, it's an expression. The best you can do with an expression is to rewrite it in a different and possibly more simplified form.

It's important to understand the difference between an equation (there's an =) and an expression, since there are many more things you can do to an equation, such as add a number to both sides, multiply both sides by a number, and so on.

With an expression, the only thing you can add is 0 (in some form) or multiply by 1 (in some form), or expand or factor to write the expression in a different form.
 
In addition to Mark44's suggestion, try to get them with the same denominator.
 
ratnesh dubey said:
hi,
i write first equation than write second equation and less the second equation from first equation than get remainder this is our solution.
This makes no sense in the context of this thread. The OP's problem is to simplify an expression. There is no equation.
 
  • #10
xeon123 said:
Hi,

I would like to solve this equation but I can't do it.

2x+1-((2x+3)/2)

Can you help me?

Thanks,

2x + 1 - ((2x + 3)/2)
2x + 1 - (x + 3/2)
2x + 1 - x - 3/2
x - 1/2


This is the step by step answer to your question.
 
  • #11
2x+1-((2x+3)/2)

=(4x+2-2x-3)/2
=(2x-1)/2:wink:
 

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