Что значит уровнение с неизвестным​

это когда,в уравнение есть одно или более неизвестных чисел,как правило их пишут через х

это когда,в уравнение есть одно или более неизвестных чисел,как правило их пишут через х

Япользуюсь интернетом не так часто, но его люблю. правила пользования интернетом: нельзя сидеть   близко, осанка должна быть ровной, стул со спинкой, пользоваться желательно не больше двух трех часов. интернет как нам друг так и враг. он работает в плохом смысле как наркотик. но с другой стороны, это наш друг и . он нам найти то, что нам нужно. с интернет- магазинов, мы можем заказать книги, игрушки, одежду, животных и инструменты, не выходя из дома. i use the internet less often, but i love it. rules for using the internet: it is impossible to sit, the posture should be steady chair with a backrest, it is desirable to use no more than two or three hours. the internet is our friend and enemy. he works in a bad way like a drug. but on the other hand, is our friend and helper. it helps us find what we need. with the help of online stores, we can order books, toys, clothing, animals and tools without leaving home

Tyrannosaurus lived throughout what is now western north america.   tyrannosaurus was a bipedal carnivore with a massive skull balanced by a long, heavy tail. relative to the large and powerful hindlimbs, tyrannosaurus forelimbs were small, though unusually powerful for their size, and bore two clawed digits. it was the largest known tyrannosaurid and one of the largest known land predators, measuring up to 12.8 m (42 ft) in length, up to 4 metres (13 ft) tall at the hips, and up to 6.8 metric tons (7.5 short tons) in weight. modern representations in museums, art, and film show tyrannosaurus rex with its body approximately parallel to the ground and tail extended behind the body to balance the head. since it was first described in 1905, tyrannosaurus rex has become the most widely recognized dinosaur species in popular culture. it is the only dinosaur that is commonly known to the general public by its full scientific name - tyrannosaurus rex. it has been frequently represented in film and on television, in literature, and on the internet.