Answer:
29
Step-by-step explanation:
Since M is the midpoint of line AB, you can set the two expressions equal to eachother 4x + 13 = 3x + 17. Simplifying it, you get x = 4. To find BM, plug 4 into the equation 3x + 17 = 3*4 + 17 which gets you 12 + 17 = 29.
