First, simplify the left side of the equation:

(54-x) ÷ 3,5 = 17:35
(54-x) ÷ 3.5 = 17:35
(54-x) ÷ 3.5 = 17 ÷ 35
(54-x) ÷ 3.5 = 0.48571428571

Next, simplify the right side of the equation:

0.48571428571 = 1,02

Now, you have:

(54-x) ÷ 3.5 = 1.02

To solve for x, multiply both sides of the equation by 3.5:

(54-x) = 1.02 * 3.5
(54-x) = 3.57

Now, subtract 54 from both sides:

54 - x = 3.57
-x = 3.57 - 54
-x = -50.43

Finally, divide by -1 to solve for x:

x = 50.43

Therefore, the value of x is 50.43.