Answer:
X: 1 5 2
Y: 4 8 5
Explanation:
Given

X: ? ? ?
Y: 4 8 5
Required
Fill in the ?'s
We have that:

When y = 4; the rule becomes

Subtract 3 from both sides


When y = 8; the rule becomes

Subtract 3 from both sides


When y = 5; the rule becomes

Subtract 3 from both sides


So, the complete table is:
X: 1 5 2
Y: 4 8 5