Plug them all in to figure out which one will give you the correct answer.
y=5x
-5=5(-1)
-5=-5. This is true.
6=5(3)
6=15 This is not true.
5=5(-1)
5=-5 This is not true.
15=5(3)
15=15 This is true.
2=5(4)
2=20 This is not true.
1=5(0)
1=0 This is not true.
Hope this helped!
-TTL
