Subtract 16 from both sides
x + 16 = 3,
x + 16 - 16 = 3 - 16,
x = -13
Another way to find the answer:
Keep trying numbers until something works!
Is x -19?
No, because -19 + 16 = -3, and not 3.
Is x -18?
No, because -18 + 16 = -2, and not 3.
Is x -17?
No, because -17 + 16 = -1, and not 3.
Is x -16?
No, because -16 + 16 = 0, and not 3.
Is x -15?
No, because -15 + 16 = 1, and not 3.
Is x -14?
No, because -14 + 16 = 2, and not 3.
Is x -13?
Yes, because -13 + 16 = 3