1. 6x-10,2=4х-2,2
6х-4х=10,2-2,2
2х=8
х=8:2
х=4
2. 15-3х+3=5-4х
-3х+4х=-15-3+5
х=-13
3. 2х-1+1=9
2х=9
х=9:2
х=4,5
1)
ctg 4π/3 =ctg (π + π/3)=ctg π/3 = √3/3
2)
sin(-2π/3)= -sin(2π/3) = - sin(π - π/3) = -sin π/3 = - √3/2
3)
cos 7π/4 = cos(2π - π/4) = cos π/4 = √2/2
Для 49 в квадрате
(1+6)в квадрате = 1+12+36=49