50 POINTS!!!!!!!!
(if you answer just for points or its a wrong answer and no effort was put fourth, then I will report and remove your answer, however a correct answer I will mark with a brainliest)
Please also provide and in detail explanation on how you solved it.
Substitution:
2x + 4y = 0
y = -8x

Basically I dont understand how to do it if it has an x value on both the top and the bottom equation.

First you see that y= -8x, so you would place that in the y variable for the question above, which means your question would now be 2x+4(-8x)=0. Now you would solve 4 time -8x which is -32x. The equation would then be 2x-32x=0. Then you would Combine Like Terms which would get you -30x=0. Then you divide -30 by 0 which gets you an x = 0. Then you would solve for y. Lets make it easy. You can plug in the x to any of the substitution problems, but I prefer doing it to y= -8x since it is easier. You will see why. You would then do, -8(0) (0 is the x value) and your answer would be 0, because -8 times 0 is well 0. Once you got this, you know your x is 0 and y is 0, so your answer would be (0,0). The reason it is easier to substitute the bottom rather than the top is because for the top, you would do 2(0) + 4y = 0, then you would solve which gets you 0+4y=0, then subtract 0-0 which is 0, then you would divide 4y by 0 which gets you an answer of 0. This is much more complex than just substituting the problem for y = -8x. I really hope this helps you out. I know it is confusing, but if you keep on solving more of these and working them out, then it will become much easier for you.