Answer:
c = 18
d = 36
Explanation:
2c = d (equation 1)
c + d = 54 (equation 2)
Use substitution by putting 2c in the place of d on the second equation.
c + 2c = 54
3c = 54
Then divide both sides by 3 to get c (18).
Then use equation 1 to find d. Do this by putting 18 in the place of c.
2(18) = d
Solve, and the answer is d = 36