Answer: x = 10.
Step-by-step explanation:
Remember that all interior angles in a triangle add to 180 degrees.
Also remember that the angle measures on one side of a line add to 180 degrees. You can represent the third interior angle as 180 - (12x - 5).
Using that representation, we can solve for x:
180 - (12x - 5) is the first degree measure
68 is the second degree measure
4x + 7 is the third degree measure.
Simplifying this, we get
x = 10.