Answer:
2.5 or 5/2
Step-by-step explanation:
Vertical angles are a pair of non-adjacent angles formed by the intersection of two straight lines. In simple words, vertical angles are located across from one another in the corners of the "X" formed by two straight lines. They are also called vertically opposite angles as they are situated opposite to each other - in other words, separated by the crossing point of the two lines, and not by the lines themselves.
that also means that they are equal.
and so,
8x + 15 = 4x + 25
4x = 10
x = 10/4 = 5/2 = 2.5
