Answer:

Step-by-step explanation:

First, add in the parentheses. a+3a=4a. Then, make subtraction into adding negatives. (-c)+5c +(-3a)+4a. It becomes 4c+a.
If D is the midpoint of CE, then CD must be equal to DE
Answer: C
since it travel at a constant speed. Calculate first its
speed of descent.
S = -3/4 mile / 1 ½ hr
S = -0.5 mile an hour
So the position of the diving bell relative to sea level 1
hour after it began its descent is
D = (0.5 mile/ hr) x 1 hr = - 0.5 mile
I believe the answer is C. It is the only one that makes sense