7 tg x – 12ctg x + 8 = 0

7tgx - 12ctgx +8 =07tgx - 12/tgx +8=0 |*tgx7tg²x +8 tgx-12 =0 D=8²+4*7*12=400t1=-2t2=6/7Возвращаемся к заменеtgx=-2x=-acrtg2 + πn, n ∈ Ztg x= 6/7x=arctg(6/7) + πn, n ∈ Z

7tgx+12/tgx+8=07tg²x+8tgx-12=0tgx=a7a²+8a-12=0D=64+336=400a1=(-8-20)/14=-2⇒tgx=-2⇒x=-arctg2+πna2=(-8+20)/14=6/7⇒tgx=6/7⇒x=arctg6/7+πn