2x+2y=8 in function form step by step ?

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.

If andrea sees that a 40-foot tree casts a 10-foot shadow then, the problem   used for that was 40 divided by 10, which was 4. now we do a reverse problem since we know the shadow casted was 15inches, we multiply 4. 15 multiplied by 4 is 90.the answer is 90 inches.