A set of numbers has the property that for any number t in the set, 2t + 2 is in the set. If -1 is in the set, which of the following must also be in the set?
I. -3
II. 1
III. 6  Pick:
A) I only B) II only C) I and II only D) II and III only E) I, II, and III
The question is which of the followingmustbe in the set, notcouldbe in the set.   If -1 is in the set so must be   2*-1+2= 
<gadget id="calculator">  2*-1+2</gadget>
<output>0</output>
0, as 0 is in the set so must be   0+2= 
<gadget id="calculator">  0+2</gadget>
<output>2</output>
2, as 2 is in the set so must be   4+2= 
<gadget id="calculator">  4+2</gadget>
<output>6</output>
6 and so on.   I onlynswer: I only.
<result>A</result>
A set of numbers has the property that for any number t in the set, 2t + 2 is in the set. If -1 is in the set, which of the following must also be in the set?
I. -3
II. 1
III. 6