7 tg x – 10ctg x + 9 = 0

Question

7 tg x – 10ctg x + 9 = 0

Answer 1

7 tg x – 10ctg x + 9 = 0 | * tgx
7 tg²x -10 +9tgx = 0
tgx = z
7z² + 9z -10 = 0
z₁ = -2                                        z₂ = 5/7
tgx = -2                                      tgx = 5/7
x = arctg(-2) + πk , k ∈Z             x = arctg(5/7 ) + πn , n ∈Z