Absolute value appears on both sides of equals sign

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Homework Help Overview

The problem involves solving the equation 5|7-3x|+2=4|7-3x|-1, which features absolute values on both sides. The original poster expresses uncertainty about how to approach solving an equation with multiple absolute value expressions.

Discussion Character

  • Exploratory, Conceptual clarification, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the implications of the absolute value expressions and the conditions under which they are positive or negative. Some suggest simplifying the equation before proceeding, while others propose substituting the absolute value expression with a variable to make the equation easier to handle.

Discussion Status

The discussion has included various suggestions for approaching the problem, including simplification and substitution strategies. While one participant claims to have solved the equation, others continue to explore different methods and perspectives without reaching a consensus.

Contextual Notes

The original poster indicates this is their first post on the forum and expresses appreciation for the community's guidance. There is an acknowledgment of the challenge posed by the equation's structure, particularly with multiple absolute values.

ECHOSIDE
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Homework Statement



solve for x:

5|7-3x|+2=4|7-3x|-1

Homework Equations



The Attempt at a Solution



7-3x>0
-3x>-7
x<3/7
{x|x<3/7} quantity is positive
{x|x>3/7} quantity is negative

I have never solved an equation with more than one absolute value quantity in it and am not sure how to start. Assistance would be wonderful!
 
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ECHOSIDE said:

Homework Statement



solve for x:

5|7-3x|+2=4|7-3x|-1

Homework Equations



The Attempt at a Solution



7-3x>0
-3x>-7
x<3/7
{x|x<3/7} quantity is positive
{x|x>3/7} quantity is negative

I have never solved an equation with more than one absolute value quantity in it and am not sure how to start. Assistance would be wonderful!

Simplify your equation first.
1) Add -2 to both sides.
2) Add -4|7-3x| to both sides.
 
SOLVED

5|7-3x|+2=4|7-3x|-1
5|7-3x|=4|7-3x|-3
|7-3x|=-3
There are no solutions.

Thanks, Mark44!
 
I know you've 'solved' it already - but something that I do for any equation with an 'inner function' is set that inner function to a variable. It makes the equation less daunting to look at (and can be easier/neater to write!).

How much easier does the following look to solve? Set a=|7-3x| and:

5a+2=4a-1

Simplify down, best you can, then put your 'a' back into the equation to finish solving.
 
mege said:
I know you've 'solved' it already - but something that I do for any equation with an 'inner function' is set that inner function to a variable. It makes the equation less daunting to look at (and can be easier/neater to write!).

How much easier does the following look to solve? Set a=|7-3x| and:

5a+2=4a-1

Simplify down, best you can, then put your 'a' back into the equation to finish solving.

That's a great suggestion. I do that with trig functions so I don't get all algebra-ey on them
 
Mark44 and mege, thank you for your guidance.
How helpful you both have been! Mege, your suggestion is wonderful. That is a skill I'm adding to my list and will not forget.
This question was my first post on physicsforums.com and I am impressed by and thankful for the responses.
Thank you for involving me in your community.
 

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