Two lines with slopes say 'm1' and 'm2' will be parallel only when m1 = m2.
Now, consider the second equation: 8x−4y=128x−4y=12
Rearranging in the slope intercept form, we get y=8x4−124=2x−3y=8x4−124=2x−3
In order for the two lines to be parallel, the slopes should be equal. Thus m=2
