Take the 2-minute tour ×
Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It's 100% free, no registration required.

I would like to know if its possible to pull $a$ out of the following equation without multiplying $b$ by $(x-y)$

$$ \frac{ 2a(x^2 - y^2)}{x - y} = b $$

Its part of a more complex problem I'm stuck on.

Cheers

share|improve this question
1  
Notice $x^2-y^2=(x+y)(x-y)$. –  Jakucha Jul 9 '12 at 2:19
    
I'm not really sure what you're asking for. Perhaps $$\frac{2(x^2-y^2)}{(x-y)}=\frac{b}{a}$$ is what you want? –  Alex Becker Jul 9 '12 at 2:19
    
Awesome, thanks Jakucha. What if the - was a + $$ \frac{ 2a(x^2 + y^2) }{ (x + y)} $$ Is it possible to pull a out without multiplying or dividing b –  user346443 Jul 9 '12 at 2:34
    
If by "pull $a$ out" you mean, "solve $2a(x^2+y^2)/(x+y)=b$ for $a$" then the answer is no. –  Gerry Myerson Jul 9 '12 at 6:13
add comment

1 Answer

up vote 1 down vote accepted

Yes indeed, you have the identity $$ x^2 - y^2 = (x-y)(x+y) $$ So, $$\dfrac{2a (x^2-y^2)}{x-y}=b \Leftrightarrow 2a(x+y)=b $$

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.