Given two straight lines L1: MX + 8y + n = 0 and L2: 2x + MY-1 = 0, if L1 / / L2, find the value of M, n,

Given two straight lines L1: MX + 8y + n = 0 and L2: 2x + MY-1 = 0, if L1 / / L2, find the value of M, n,

If two lines are parallel, the slope is equal
We can find that M = 4
I can't find out n, but n ≠ - 2