Помогите решить 11sin2x-7cos2x=11

22SinxCosx -7(Cos²x - Sin²x) = 11*122SinxCosx - 7Cos²x + 7Sin²x = 11*(Sin²x + Cos²x)22SinxCosx - 7Cos²x + 7Sin²x = 11Sin²x + 11Cos²x22SinxCosx - 7Cos²x + 7Sin²x - 11Sin²x -11 Cos²x = 022SinxCosx -18Cosx -4Sin²x = 011SinxCosx -9Cos²x -2Sin²x = 0 | :Cos²x ≠ 011tgx -9 -2tg²x = 0tgx = e2y² -11y +9 = 0D = b² - 4ac = 121 - 72 = 49y₁ =(11+7)/4 = 18/4=9/2=4,5у₂ = (11-7)/4 = 1а) у₁ = 4,5tgx = 4,5x = arctg4,5 + πk , k ∈Zб) у₂ = 1tgx = 1x = π/4 + πn , n ∈ Z