(3 + 4i)(3 - 4i + 2 - i) = (3 + 4i)(5 - 5i) = 5(3 + 4i)(1 - i) = 5(3 - 3i + 4i - 4i²) =
5(i + 3 - 4·(-1) = 5(i + 3 + 4) = 5(i + 7) = 5i + 35
i² = -1.
6y-y²=0
y(6-y)=0
y=0 6-y=0
y=6
Ответ: 0; 6.
Ctg(2π-5π/13)=-ctg5π/13
cos(3π-π/3)=cos(π-π/3)=-cosπ/3=-1/2
X^3=3
26*x^3=78
x=1
както так