It's 12. The smallest number both 6 and 4 multiply to is 12 (it doesn't have to be when they multiply together just a number both can get to)
1). Add 4 to each side of the equation.
2). Multiply each side by 7 .
3). Step numbly to one side, as the answer
comes shooting off the page at you.
Hey! The answer would be AB=AD because you need the given side length to come to a consensus that the sides are congruent as well, since one angle is already proven congruent. The side is the last missing one.