In a certain sequence of numbers, each term after the first is found by doubling and then adding $3$ to the previous term. If the seventh term of the sequence is $125$, what is the first term?
125-3=122
122/2=61
61-3=58
58/2=29
29-3=26
26/2=13
13-3=10
10/2=5
5-3=2
2/2=1
1-3=-2
-2/2=-1
Term 7: 125
Term 6: 61
Term 5: 29
Term 4: 13
Term 3: 5
Term 2: 1
Term 1:-1
The first term is -1