The meaning of vertical angles are two congruent angles formed by the intersection of two straight lines.
In this exercise is given the image of a pair of vertical angles and it is asked to find the value of y. In order to do that, you should put both expressions representing the angles together in a form of equation, since vertical angles are equals in measure.
9y+7=2y+98 Subtract 2y in both sides
7y+7=98 Subtract 7 in both sides
7y=91 Divide by 7 in both sides to isolate y
y=13
The value of y is 7, and the measure of each angle is 124 degrees.