Question 12345
5d+9-4d=51-5d
d +9 = 51 - 5d


Add 5d to each side:
d + 5d + 9 = 51 - 5d + 5d
6d + 9 = 51


Subtract 9 from each side:
6d + 9 - 9 = 51 - 9
6d = 42
d= 7


R^2 at SCC
d= 7