Answer:
Part A: 2D + 3 = A
Note: I have likely given you the answer to the whole problem. See below.
Step-by-step explanation:
Givens
Comment
You have to pay the most attention to Alan and Bruce. Once you have equations for those two. Cecil's weight is just the sum of those two.
Alan
Alan = Twice*Dylan + 3 or
A = 2*D + 3
Bruce
Bruce = three * Dylan - 12
B = 3*D - 12
Cecil
Cecil = Alan + Bruce
C = A + B
Note
The last equation shows you how to combine the first two.
C = A + B
A = 2D + 3
B = 3D - 12
C = 2D + 3 + 3D - 12
C = 5D - 9