Question

поможіть мені будь-ласка даю 80 балів!!!!!​

Answer 1

1) a1 = 2

d = -3

Sn = (2a1 + d(n-1) / 2) × n

S7 = (2×2 + (-3×6) / 2) × 7 = (4 - 18 / 2) × 7 = -49

Ответ : S7 = -49

2) 1;2;4;8;16;32;

3;12;48;192;

3) b1 = 4

q = 3

bn = b1 × q^n-1

b4 = 4 × 3³ = 108

Ответ : b4 = 108

4) 3;9;27;..

q = bn/bn-1 = 27/9 = 3

b6 = b1 × q⁵ = 3 × 243 = 729

Ответ : b6 = 729

5) b1 = -5

q = 2

S5 = -5(2⁵-1) / 1 = -5 × 31 = -155

Ответ : S5 = -155

6) 3;6;12;..

b1 = 3

q = 6/3 = 2

S6 = 3(2⁶-1) / 1 = 3 × 63 = 189

Ответ : S6 = 189