If x + 3 is a multiple of 3, which of the
following is not a multiple of 3?
(a) x
(b) x + 6
(c) 6x + 18
(d) 2x + 6
(e) 3x + 5

The answer is E because if x+3=0 then x=-1 which is the multiple of 3x-1
1)x
we have x so its -3
2)x+6
-3+6=3 its a multiple of 3 (3x1)
3)6x+18
6(-3)+18
0 is a multiple of 3 (3x0)
4)2x+6
2(-3)+6
0 is a multiple of 3
5)3x+5
3(-3)+5
-1 is not a multiple of 3