Convert to slope intercept form (y=mx+b).
2x-4y=8
subtract 2x from each side
2x-2x-4y=-2x+8
-4y = -2x+8
divide by -4
y = -2/-4 x +8/-4
y = 1/2 x -2
it is now in slope intercept form
-4y=-2x+8
y=1/2x-2
