Question

СРОЧНО!!!!! ПОМОГИТЕ ПОЖАЛУЙСТА!!!!! 10-11 класс 

Answer 1

$\frac{cos64cos4-cos86cos26}{cos41cos71-cos49cos19} = \frac{cos64cos4-cos(90-4)cos(90-64)}{cos41cos71-cos(90-41)cos(90-71)} =$$\frac{cos64cos4-sin4sin64}{cos41cos71-sin41sin71} = \frac{cos(64+4)}{cos(41+71)} = \frac{cos68}{cos112} = \frac{cos68}{-cos68} =-1$
-1  -  5%
x  -  100%
x= -1*100/5
x= - 20
Ответ: - 20

Answer 2

Смотреть во вложении