А) 3x-xy-3y+y^2=3(x-y)-y(x-y)=(3-y)(x-y)
б) ax-ay+cy-cx-x+y=a(x-y)-c(x-y)-1(x-y)=(a-c-1)(x-y)
3^3 *3^-2 *3^-4 :3^-2= 3^-1 =1/3
10^4 *10^-3 =10
cos(5π/3-x)+cosx = cos5π/3· cosx + sin5π/3·sinx + cosx = 0.5 cosx - 0.5√3·sinx + cosx=
√0,81*а^3=√0,9^2*a^2*a=0,9a√a