(2,1 • 3,2 - 0,72) х = 5,4.

To solve this equation for x, we need to perform the operations within the parentheses first and then solve for x.

Given: (2.1 * 3.2 - 0.72) * x = 5.4

First, calculate the result inside the parentheses: (2.1 * 3.2 - 0.72) = 6.72 - 0.72 = 6

Now, the equation becomes: 6 * x = 5.4

To find x, divide both sides of the equation by 6: x = 5.4 / 6 x = 0.9

Therefore, the solution for x is 0.9.