Answer:
x = 4
Explanation:
The figure in the picture is a parallelogram. In parallelograms diagonals bisect each other. That means that they divide each other in half. That means that 6x + 1 is the same as 4x + 9.
6x + 1 = 4x + 9
2x + 1 = 9
2x = 8
x = 4