Question

I need the answer and the work!
you have to find n.

Answer 1

Tell you what I'll do: I'll show you the work, for two of them.
Then, knowing how to do it, you'll find the answers.
Deal ?

#1). n + (-13) = -12

Remove the parentheses
on the left side: n - 13 = -12

Add 13 to each side: n = 1

================================

#3). -15 + n = 3

Add 15 to each side: n = 18


OK. Look those over, understand how they're done, then TAKE IT !