Выразите сторону четырехугольника обозначенную буквой X на рисунке через его стороны а и b.

My country house has two floors. On the first floor we have two rooms and a kitchen. On the first floor we have three rooms: a living room and two bedrooms.
In the dining room on the ground floor we have a large round table with several chairs around it and two sideboards. In the guest room on the ground floor we have four armchairs, a sofa, a fireplace and a large TV. The kitchen has a stove, sink, microwave and frige. We have a computer and a bookcase, a small table and a sofa in the living room. We have beds in the bedrooms. My country house is special to me because it is very comfortable. It is beautifully decoratedMy country house has two floors. On the first floor we have two rooms and a kitchen. On the first floor we have three rooms: a living room and two bedrooms.
In the dining room on the ground floor we have a large round table with several chairs around it and two sideboards. In the guest room on the ground floor we have four armchairs, a sofa, a fireplace and a large TV. The kitchen has a stove, sink, microwave and frige. We have a computer and a bookcase, a small table and a sofa in the living room. We have beds in the bedrooms. My country house is special to me because it is very comfortable. It is beautifully decorated