Substitute 2 for d.
[tex]2(d + 4d) \\ 2(2 + (4 \times 2)) \\ 2(2 + 8) \\ 2(10) \\ 20[/tex]
Answer: d = 12
2(2 + 4d)
Disturbte the 2 time everything and you get
4 + 8D add alike variable and the answer is d=12