What is the slope of the line whose equation is 2x−4y=102x−4y=10 ?

2x - 4y = 10
2x - 4y + 4y = 10 + 4y ... see note 1
2x = 10+4y
2x-10 = 10+4y-10 ... see note 2
2x-10 = 4y
4y = 2x-10
4y/4 = 2x/4-10/4 ... see note 3
y = (1/2)x - 5/2 

note 1: add 4y to both sides
note 2: subtract 10 from both sides
note 3: divide every term by 4

After all that work, we end up with y = (1/2)x - 5/2 
it's in y = mx+b form where m = 1/2 is the slope