SOLUTION: I had the problem 18 - n = 21 and I found the answer doing this: 18 - n = 21 18 - n - 18 = 21 - 18 -n = 3 -1(-n) = -1(3) n = -3 The thing I'm struggling with is justifying th

Question 682728: I had the problem 18 - n = 21 and I found the answer doing this:
18 - n = 21
18 - n - 18 = 21 - 18
-n = 3
-1(-n) = -1(3)
n = -3
The thing I'm struggling with is justifying the steps like is that step distributive, associative, commutative etc.?
Thanks!
Answer by lynnlo(4176) (Show Source): You can put this solution on YOUR website!
commutative
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