Answer:
The value of x is 5.
Step-by-step explanation:
We are given the following in the question:
[tex]\triangle CDE[/tex]
[tex]\angle CDE = (3x-14)^{\circ}\\[/tex]
[tex]\angle ECD = (3x+12)^{\circ}[/tex]
∠DEF = (8x−12) degrees
Exterior angle sum property:
The angle DEF is the exterior angle and angle CDE and angle ECD are the opposite interior angle.
Thus, we can write the equation:
[tex](3x-14) + (3x+12) = (8x-12)\\\Rightarrow 6x - 2 = 8x - 12\\\Rightarrow -2x = -10\\\Rightarrow 2x = 10\\\Rightarrow x = 5[/tex]
Thus, the value of x is 5.