These figures?
well the most simple figures can be circle, triangle, square, etc... and you can write on how you got them.
U = -b + 21 . . . (1)
u = -2b + 30 . . . (2)
Equating (1) and (2),
-b + 21 = -2b + 30
-b + 2b = 30 - 21
b = 9
u = -9 + 21 = 12
Therefore, (b, u) = (9, 12).
