Answer: B. 
Step-by-step explanation:
The notation to express a dependent variable is given by :-
, where Y is depending variable which is dependent upon x ( independent variable).
The given statement : The distance an airplane travels depends on how much time it spends flying.
Here , Independent variable : Time
Dependent variable : Distance
Then , the notation to express distance (dependent variable) the airplane flies in 20 minutes is given by :-

OK. Hold on tight. Here we go.
Remember ... the "solution" is the number that 'g' must be
in order to make the equation a true statement.
The original equation: You said that -2 = g - 9
Now, let's add 9 to each side: 7 = g .
7%, 13%, 0.15, 4/25, 21/100, 0.28
Answer: (A) CDD
if D=C^-1
then
C D D = (C C^-1) D = I D = D
(where I is the identity matrix)