First, let's simplify the expression:

|1,2x + 1,8| * (7x - 0,21) = 0

We can rewrite the absolute value as two separate equations:

(1.2x + 1.8)(7x - 0.21) = 0
or
(-1.2x - 1.8)(7x - 0.21) = 0

Now we can solve each equation separately:

(1.2x + 1.8)(7x - 0.21) = 0
8.4x^2 - 0.252x + 10.8x - 3.078 = 0
8.4x^2 + 10.548x - 3.078 = 0

(-1.2x - 1.8)(7x - 0.21) = 0
-8.4x^2 + 2.52x - 10.8x + 0.378 = 0
-8.4x^2 - 8.28x + 0.378 = 0

Now, we can solve the quadratic equations to find the values of x that satisfy the equation.