If the left hand side of the two equations are multiple of each other, then the system is either dependent or inconsistent (depending on the right hand side).
In this case, the system is independent, because the two left hand sides are not proportional. For example, in order to have the same x coefficient you have to multiply the first equation by -2, and you get
[tex] 4x-8y = 16 [/tex]
and the two left hand sides are different. So, the system is independent.