4,5x * 1,8 = 9 * 2,7

8,1x = 24,3

x = 24,3 : 8,1

x = 3

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4)

0,6x * 1 5/6 = 7 1/3 * 0,75

3/5x * 11/6 = 22/3 * 3/4

11/10x = 11/2

x = 11/2 * 10/11

x = 5