Question 776061
Let n = the number
The  problem statement becomes
(1) 2*(n + 3) = n - 1 or
(2) 2*n + 6 = n - 1 or
(3) n = -7
Use (1) to check your answer.
Is (2*(-7+3) = -7-1)?
Is (-14+6 = -8)?
Is (-8 = -8)? Yes
Answer: The number is -7.