Решите уравнение:

1) 14/15 * x = 2/5

x = 2/5 : 14/15

x = 2/5 * 15/14 = 6/14 = 3/7

2) x * 4 = 7

x = 7/4

x = 1(3/4)

3) 5x = 1/2

x = 1/2 : 5 = 1/2 * 1/5 = 1/10

x = 1/10

4) 1/4 x = 1 + 3

1/4 x = 4

x = 4 : 1/4 = 4 * 4 = 16

x = 16