Question

Используя основное свойство дроби, найдите значение x, при котором данное равенство верно: 1) x/5 = 4/20; 2)6/x = 18/30; 1/3 = 7/x; 42/78 = x/13 .

Answer 1

Х/5 = 4/20
4х/20 = 4/20
4х = 4
Х = 1
=====
6/Х = 18/30
6/Х = 6/10
Х = 10
=====
1/3 = 7/Х
7/21 = 7/Х
Х = 21
=====
42/78 = Х/13
42/78 = 6х/78
42 = 6х
Х = 7