Calculus
posted by Liz .
Find dy/dx
y = (x+y)/(x√2)
I know that you can simplify the problem by arranging it to:
y = (x)/(x√2) + (y)/(x√2)
but I don't know where to go from here

I am not certain what you mean by x√2.
Please explain 
apply quotient rule:
http://www.mathwords.com/d/derivative_rules.htm
y'=[(1+y')(x√2)(x+y)(√2)]/(x√2)^2
implicit differentiation:
http://www.cliffsnotes.com/study_guide/ImplicitDifferentiation.topicArticleId39909,articleId39882.html
solve for y' 
I agree with Bob. A clarification is necessary.
(x)/(x√2) looks like 1/√2 to me, and the derivative of that term is zero.