РЕШЕНИЕ:

q = -3

S7 = b1(q⁷ - 1) / (q - 1) = (-2) ((-3)⁷ - 1) / ((-3) - 1) = (-2) ∙ (-2188) / (-4) = - 1094

Ответ: - 1094

РЕШЕНИЕ:

___− 19___ ≥ 0
(x+5)²−6

(x+5)²−6 < 0

x² + 10x + 25 – 6 < 0

x² + 10x + 19 < 0

x² + 10x + 19 = 0
D = 100 – 4∙1∙19 = 100 – 76 = 24 = 6∙4 = (2√6)²

x₁ = ( – 10 + 2√6) / 2 = – 5 + √6

x₂ = ( – 10 – 2√6) / 2 = – 5 – √6

____ + ________ – _________ +
__________o____________o________
______ – 5 – √6_____ – 5 + √6

Ответ: ( – 5 – √6 ; – 5 + √6)

РЕШЕНИЕ:


S ABCD = S ∆ACM

В ∆ACM
AC = 6
CM = 8
AM = 2 EF = 2 ∙ 5 = 10

p = ( 6 + 8 + 10 )/2 = 12

S = √ 12 ( 12 - 6 )( 12 - 8 )( 12 - 10 ) = √ 576 = 24

Ответ: 24

РЕШЕНИЕ:



R =√ 32 ² + ( 120 /2)² = √ 4624 = 68

d = 2R = 2 * 68 = 136

Ответ: 136