To solve this equation, we can start by distributing the coefficients on each side:

4/9 8,1 - 4/9 3,6x = 2,1 5/7 - 2,1 3/7x

Next, we can simplify the expressions by multiplying the fractions:

36/9 - 14,4/9x = 10,5/7 - 6,3/7x

Now, we can further simplify the fractions:

4 - 1,6x = 1,5 - 0,9x

Next, we can combine like terms on each side of the equation:

4 - 1,5 = 1,6x - 0,9x

2,5 = 0,7x

To solve for x, we divide both sides by 0,7:

x = 2,5 / 0,7

x ≈ 3,57

Therefore, the solution to the equation is x ≈ 3,57.