Since we have that BD is the median, it divides the segment or side of the triangle into two equal parts. Then, we have that:

Then, we need to solve the equation for x, and to do so, we need to:
1. Subtract 2x, and 10 from both equations:

2. Since we have like terms, then we have:

In the previous step, we divide both sides of the equation by 4 and then simplify the resulting fraction.
Hence, the value for x = 1/2. The length of AC is the sum of AD + CD or twice the value of one of them:

Therefore, the length of AC is

AC = 26 units.