Correct option :

Steps to derive the correct option :
Given :
- Lines u and v are parallel
- Measure of an angle = 12x - 4
- Measure of it's corresponding angle = 10x + 10
Since these angles are corresponding angles and lie on two parallel lines, their value will be equal.
Which means :






Thus, the value of x = 7.
Let's place 7 in the place of x and see if their value matches :



Thus, ∠12x - 4 = 80°



Thus, ∠10x + 10 = 80°
Since the value of these two angles are equal, we can conclude that we have found out the correct measure of each angle.
Therefore, the correct option is - (A) 12x - 4 = 10x + 10; x = 7