55:з+19=30

To solve this equation, we need to isolate the variable 'з'.

First, let's subtract 19 from both sides of the equation:

55 - 19 + з = 30 - 19

The equation becomes:

36 + з = 11

Next, let's subtract 36 from both sides of the equation:

36 + з - 36 = 11 - 36

Simplifying further:

з = -25

So the value of 'з' is -25.