Ответ: tgx-5/tgx-4=0tg²x-4tgx-5=0  tgx≠0tgx=aa²-4a-5=0a1+a2=4 U a1*a2=-5a1=-1⇒tgx=-1⇒x=-π/4 +πna2=5⇒tgx=5⇒x=arctg5+πn