3cos²2x - 5sin²x - sin2x = 0 5sin²x + sin2x - 3cos²x = 0 5sin²x + 2sinxcosx - 3cos²x = 0 |:cos²x 5tg²x + 2tgx - 3 = 0 5tg²x + 5tgx - 3tgx - 3 = 0 5tgx(tgx + 1) - 3(tgx + 1) = 0 (5tgx - 3)(tgx + 1) = 0 1) 5tgx - 3 = 0 5tgx = 3 tgx = 3/5 x = arctg(3/5) + πn, n ∈ Z 2) tgx + 1 = 0 tgx = -1 x = -π/4 + πk, k ∈ Z Ответ: x = arctg(3/5) + πn, n ∈ Z; -π/4 + πk, k ∈ Z.