a) To solve for d in the equation 54 = 9d, we can divide both sides by 9:
54/9 = d
6 = d
Therefore, d = 6.
b) To solve for n in the equation n + 2 = -14 - n, we can start by adding n to both sides:
n + n + 2 = -14
Next, we can combine like terms:
2n + 2 = -14
Then, we can subtract 2 from both sides:
2n = -16
Finally, we can divide both sides by 2:
n = -8
Therefore, the solution is n = -8.