Making Y the subject of equations:i) c=3m/2m+y ii) xy/x+y = k.I'm having trouble isolating the y pronumeral for both equations, so if you could...

I see you already have two answers, but I thought I would
give it a go anyways ;)

i)
c=3m/(2m+y)

The first step is to get y in the numerator
instead of the denominator.  We can do this by multiplying both sides by
(2m+y):

(2m+y)c =
3m(2m+y)/(2m+y)

On the right hand side of the equation you
can solve (2m+y)/(2m+y) = 1 to give:

(2m+y)c =
3m

Next you want to get y out of the brackets.  To do this
multiply c into the brackets:

2mc + yc =
3m

Now we can begin to isolate y.  Mvoing 2mc to the right
hand side of the equation changes its sign to negative:

yc
= 3m - 2mc

Now we can divide both sides the the equation by
c, and eliminate c/c = 1 on the left hand side of the
equation:

y = (3m - 2mc)/c

In
the above equation m can be factored out to give the final
answer:

y = m(3 -
2c)/c

ii) xy/(x+y) =
k

On first glance this one looks more complicated, but lets
follow a similar method as in i) and see what happens.  First, get rid of the
denominator by multiplying both sides by (x+y):

xy =
(x+y)k

Next, expand the right hand side of the
equation:

xy = kx+ky

Group all
variables containing the unknown y:

xy-ky =
kx

Factor out y:

y(x-k) =
kx

And finally, isolate
y:

y = kx /
(x-k)

When you are approached with questions
like this just remember, elimate fractions, expand, isolate, factor if necessary
;)