if x+y=6 and 3x-y=4 then x-y is equal to?

x + y = 6 ...... [1]
3x - y = 4 ...... [2]

[2] - [1] :
(3x - y) - (x + y) = 4 - 6
2x - 2y = -2
x - y = -1

We can solve this set of simultaneous equations by adding both equations together :

[x + y = 6]
(+)[3x - y = 4]
4x = 10
So x = 2.5

y = 6 - x
y = 6 - 2.5
y = 3.5

Thus, x - y = 2.5 - 3.5 = - 1

Hope this helps !!!!!!!!!!!!!!!!!!!

x + y = 6
3x - y = 4
x = 5/2, y = 7/2
x - y = -1

yes

x + y = 6 .. (1)
3x - y = 4 ... (2)
(1) - (2)
-2x + 2y = 2
x - y = -1

4x = 10
x = 5/2
y = 7/2
x - y = 1