First, I should point out that g(x) should be written as g(x)=(x+2)/3, otherwise the problem is confusing.
(A) 
(B) Since 
and 
, it holds that
for all x. This means the composed functions are *identical*
Yes, you would try to simplify the equation as much as possible in order to get the variable.
Answer:
option c)
d = 1
Step-by-step explanation:
Given the equation in the question,
-3d / (d² - 2d - 8) + (3 / d-4) = (-2 / d+2)
quadratic factorisation
-3d / (d+2)(d-4) + (3 / d-4) = (-2 / d+2)
-3d / (d+2)(d-4) = (-2 / d+2) - (3 / d-4)
taking LCM on right side
-3d / (d+2)(d-4) = ( -2(d-4) - 3(d+2)) / (d+2)(d-4)
canceling (d+2)(d-4) on both sides
-3d = -2(d-4) - 3(d+2)
-3d = -2d + 8 - 3d - 6
-3d + 2d + 3d = 8 - 6
2d = 2
d = 1
