Absolute value appears on both sides of equals sign

AI Thread Summary
The discussion revolves around solving the equation 5|7-3x|+2=4|7-3x|-1, which involves absolute values. Initial attempts to solve the equation reveal that simplifying leads to |7-3x|=-3, indicating no solutions exist. Participants suggest setting the inner function, |7-3x|, as a variable to simplify the problem further, making it easier to manage. This approach is appreciated by the original poster, who finds the community's guidance helpful. Overall, the thread emphasizes strategies for handling equations with multiple absolute values and the value of community support in problem-solving.
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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