Answer:
x = 5
Explanation:
Comment
BD is already given to you as bisected. AC must also be bisected. That means that 6x and 7x - 5 must the the same value. Then and only then will the figure be a parallelogram. (a four sided figure is a parallelogram if the 2 diagonals are bisected.
Equation
6x = 7x - 5 Subtract 6x from both sides
Solution
6x - 6x = 7x - 6x - 5 Simplify
0 = x - 5 Add 5 to both sides
5 = x - 5 + 5 Simplify
x = 5