Answer:

Step-by-step explanation:

First, you should distribute the -1 on the right.

Next, add 8n to both sides. This should cancel out the 8n.

Now, add 8 to both sides. This will get n by itself.

Your answer is n = -2.
Answer:
-3 does not belong because it is not an algebraic expression unlike the others.
15 devided by 2 equals 7.5
63+82+m∠DCE=180
145+m∠DCE=180
m∠DCE=35