Corresponding Angles
They are formed when a transversal line cuts across two straight lines.
The horizontal line that is shown in the image cuts across the two straight and parallel lines, thus the angles marked with variables are corresponding and congruent.
Congruent angles have the same measure, thus:
4x - 14 = x + 85
Now we solve the equation
Adding 14
4x = x + 85 + 14
Subtracting x
3x = 85 + 14
Operating
3x = 99
Dividing by 3:
x = 99/3 = 33
x = 33