Решите уравнение

7cos (2x-π/3) = - 3.5

7cos (2x-π/3) = - 3.5|:7

cos (2x-π/3) = - 1/2

2x-π/3 = + - (π-arccos1/2) + 2πn, n∈Z

2x-π/3=+-2π/3+2πn, n∈Z

2x=+-2π/3+π/3+2πn, n∈Z |:2

x=+-π/3+π/6+πn, n∈Z

x1=π/2+πn, n∈Z x2=-π/6+πn, n∈Z