3,-6;.......,..,..; S5-???

Question

3,-6;.......,..,..; S5-???

Comments

какая прогрессия?

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геометрия

Answer 1

Q= -6:3 = -2
b3 = 3*(-2)² = 12
b4 = 3*(-2)³ = -24
b5 = 3*(-2)^4 = 48
S5 = 3+12+48-6-24 = 63-30 = 33