Which table represents a linear function?

Table 1: X=1,2,3,4
Y=-2,-6,-2,-6

Table 2: X=1,2,3,4
Y=2,-5,-9,-14

Table 3: X=1,2,3,4
Y=-2,-10,-18,-26

Table 4: X=1,2,3,4
Y=-2,-4,-8,-16

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