Cos2x = 1/2
2x = + - arcCos 1/2 + 2Пn, n э Z
2x = + - П/3 + 2Пn, n э Z
x = + - П/6 + Пn, n эZ
![\left \{ {{x^{2}+6x-27\leq0} \atop {x+4<0}} \right.\\\\\left \{ {{(x+9)(x-3)\leq 0} \atop {x<-4}} \right.](https://tex.z-dn.net/?f=%5Cleft%20%5C%7B%20%7B%7Bx%5E%7B2%7D%2B6x-27%5Cleq0%7D%20%5Catop%20%7Bx%2B4%3C0%7D%7D%20%5Cright.%5C%5C%5C%5C%5Cleft%20%5C%7B%20%7B%7B%28x%2B9%29%28x-3%29%5Cleq%200%7D%20%5Catop%20%7Bx%3C-4%7D%7D%20%5Cright.)
+ - +
1) _________[- 9]_________[3]_________
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2) _______________(- 4)_____________
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x ∈ [-9 ; - 4)
- 9 + (- 8 ) + (- 7 ) + (- 6 ) + (- 5 ) = - 35
Ответ : - 35
-6x²+8x-10=0|:(-2)
3x²-4x+5=0
D=16-4*3*5=-44(D<0 ⇒нет корней)
Ответ: ∅
Log81(6^4)*log6(9) = log9^2 (6^4) * log6(9) = 4/2 log9(6) * log6(9) = (дробь)(4*log9(6))/(9*log9(6)) = 4/2 = 2