Question

44/x+y=30/x-y=10,55/x+y+40/x-y=13

Answer 1

I assume you mean 
44/(x+y) +30/(x-y) =10 & 55/(x+y) +40/(x-y) =13 

Please note that you should use brackets properly without which the question changes from what you wanted to ask and some answeres may answer as asked and that will give you answer to the question as asked and not as you intended to ask. 
I have also assumed that + 10 is a misprint and is = 10. 

Let 1/(x+y) = a and 1/(x-y) = b 
=> 44a + 30b = 10 and 55a + 40b = 13 
Solving, a = (10*40 - 13*30)/(44*40 - 55*30) = 10/110 = 1/11 
and b = (10 - 44/11)/30 = 1/5 

=> 1/(x+y) = 1/11 and 1/(x-y) = 1/5 
=> x + y = 11 and x - y = 5 
Adding 2x = 16 => x = 8 and y = 11 - 8 = 3 

Answer: 
x = 8 and y = 3. 

Answer 2

Check this out...

Itried it just now.....