Final answer:
To find the value of x, set up an equation using the sum of angles in a triangle and solve for x.
Step-by-step explanation:
To find the value of x, let's first analyze the given information. We are given that the measure of angle MZADF is 140 degrees, M2BDE is 8r+20 degrees, and mZEDC is 12x+25 degrees. We need to find the value of x. Since the sum of all angles in a triangle is 180 degrees, we can set up the equation: 140 + (8r+20) + (12x+25) = 180. By simplifying and solving for x, we can find the value of x.