Question

derivative with respect to x

Answer 1

z= (x+y)/(x-y)

Answer 2

what do u mean "respect to x"

Answer 3

y is constant

Answer 4

ok,.. use this formula (division rule)
if z=u/v then z'=(u'v-uv')/v^2
does this help

Answer 5

if u=x+y --->u'=....?
v=x-y --->v'=....?

Answer 6

u' = 1?
v'=1?