The angles in the diagram are vertically opposite angles. Therefore, they are equal. Base on there congruency, the value of x is -14.
What are vertical angles?
Vertical angles are angles that share the same vertex. Vertical angles are a pair of opposite angles formed by intersecting lines.
Vertical angles are congruent.
Therefore,
9x + 210 = 4x + 140
subtract 4x from both sides
9x - 4x + 210 = 4x - 4x + 140
5x + 210 = 140
subtract 210 from both sides
5x + 210 - 210 = 140 - 210
5x = -70
x = -70 / 5
x = -14
learn more on vertical angles here: https://brainly.com/question/26664800
