Answer:
u – 9 = -7 u + 7
-u -u
-9 = -8u + 7
-7 - 7
-16 = -8u
This happened because first I isolated the variable so there is only on one side.
Then I solved the actual numbers.
Since there are two negatives they cancel out.
Finally divide both sides by 8.
This is equal to the answer are u = 2.
Hope this helps