Answer: 20
Explanation:
Since Line l is a segment bisector, we know that AM and MC are equal to each other.
6y-4=2y+12 [subtract both sides by 2y]
4y-4=12 [add both sides by 4]
4y=16 [divide both sides by 4]
y=4
Now that we have y, we plug that into AM.
6(4)-4 [multiply]
24-4 [subtract]
20
Now, we know that AM is 20.