help??

Hello?

I'm pretty sure it's the fourth one because it's none of the first three, but you need to use parentheses to identify what goes with what. Is it one-fourth x or is it 1 over 4x, and so on.  You could verify which one it is by actually plotting a few points on a graph.   

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I'm assuming that the 4th one is  y  = (1/4)x - 2

If the first one is  y = 3x^3......then this is non-linear

All the rest ARE linear

[ The third one is a horizontal line at y = 15.3  ]

All the rest ARE linear   

Not if that last one is 1 over 4x.  I'm not going to answer any more of these where you have to guess what the problem even is. 

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