Answer :

AL2006
You could get two different functions out of this:

2x + 2y = 8

1).  'y' as a function of 'x'

Subtract  2x  from each side:  2y  = -2x + 8

Divide each side by  2 :          y  =  -x + 4


2).  'x' as a function of 'y' :

Subtract  2y  from each side:    2x  =  -2y + 8

Divide each side by  2 :          x  =  -y + 4

Those two functions look the same, but that's just because the original
equation given in the problem was so symmetrical.  In general, they're
not the same function.
Starting with 2x +  2y = 8

The first step is to subtract the monomial including x from both sides.
2x + 2y = 8
-2x          -2x
The result is 2y = -2x + 8

The next step is to isolate y, which we must divide both 2y and -2x + 8 by 2 to achieve.
2y = -2x + 8
/2          /2
The result is y = -x + 4, which is now in function(slope-intercept) form.