Answer:
a ) R(x)  = 0,2933*e∧0,2387*t
b) 5,9042 billions of dollars
Step-by-step explanation:
The rate of change in revenue  dR/dt for Priceline Group is
dR/dt =  0,07*e∧0,2387*t
dR = (0,07*e∧0,2387*t ) * dt
∫dR = ∫ (0,07*e∧0,2387*t ) * dt    between 2004  to 2013  ( t = 4 stands for 2004 and t = 13 stands for 2013 )
R(x)  =  (0,07/ 0,2387)*e∧0,2387*t )
R(x)  = 0,2933*e∧0,2387*t
Then
R(4)  = 0,2933*e∧0,2387*4
R(4) = Â 0,2933*2,5981
R(4) = Â 0,7602 billions of dollars
R(12)  = R(4) +  0,2933*e∧0,2387*12
R(12) Â = 0,7602 + Â 5,1440
R(12) Â = Â 5,9042 billions of dollars