405; 605
Объяснение:
b1 = 5
b2 = 15
q = b2 : b1
q = 15 : 5 = 3
b5 = b1 • q^4
b5 = 5 • 3^4 = 5 • 81 = 405
S5 = b1 + b2 + b3 + b4 + b5
S5 = 5 + 5•3 + 5•3•3 + 5•3•3•3 + 5•3•3•3•3 = 5 + 15 + 45 + 135 + 405 = 605
