Answer:
16
Explanation:
The two triangles are similar, and the larger one is twice the size of the smaller one. That means the segment marked 10x-72 is twice the length of the one marked 3x-4.
2(3x -4) = 10x -72
6x -8 = 10x -72 . . . . .eliminate parentheses
64 = 4x . . . . . . . . . . . add 72-6x
16 = x . . . . . . . . . . . . . divide by 4