(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

[tex]\left( {x + y} \right)y' = x - y[/tex]

2. Relevant equations

Back of book:

[tex]x^2 - 2xy - y^2 = C[/tex]

3. The attempt at a solution

I'm not sure how to start this problem. In the examples in the book, they make a substitution,v=something, and all that was left were v's and x's, or v's and y's. Usually it was an expression that appeared twice, so making a substution made sense. But if I set v=x+y, or v=x-y, I'm still left with v's, x's & y's. How do I start this one?

Thanks in advance!

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# Homework Help: Ode substitution method

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