Пошаговое объяснение:

3.34:

8/x=35/7    

8/x : 35/7 = 1

8*7/35x = 1

8/5x = 1

8/5 = x

x = 1,6

32/12 = y/9    

32 * 9/12y = 1

8 * 9/3y = 1

8 * 3/y = 1

24 = y

y = 24

54/x = 9/12    

54/x = 3/4

54 * 4/3x = 1

18 * 4/x = 1

72 = x

4,2/12 = 35/x  

2,1/6 = 35/x

2,1x/6 * 35 = 1

2,1x/3 * 2 * 7 * 5 = 1

0,7x/2 * 7 * 5 = 1

0,1x/10 = 1

0,1x = 10

x = 10 : 1/10

x = 10 * 10 = 100

3.35:

x/55 = 4/11 : 1,6

11x/55 * 4 = 1/1,6

x/5 * 4 = 1/1,6

1,6x/5 * 4 = 1

0,4x/5 = 1

0,4x = 5

x = 12,5

(1 + 5/6) : y = 55:12

11/6 * 12 = 55y

2 * 11 = 55y

2 * 11/55 = y

2/5 = y

y = 0,4

8 : 54 = 4/9 : x

8/54 = 4/9x

8 * 9x/54 * 4 = 1

2x/6 = 1

2x = 6

x = 3

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Решить не смог ни я, ни калькулятор. Если интересно, то калькулятор выдаёт 144/145, извини.

y : (2 + 5/12) = 18 : 87

y/29 = 18/87

87y/29 * 18 = 1

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12/y = (2 + 2/9) : (3 + 1/3)

12/y = 20/9 : 10/3

12/y = 20 * 3/9 * 10

12/y = 2/3

12 * 3/2y = 1

6 * 3/y = 1

18 = y

y = 18

1,3 : 10 = x : (3 + 11/13)

1,3/10 = 13x/50

1,3 * 50/10 * 13x = 1

0,1 * 5/x = 1

0,5 = x

x = 0,5