Being the midpoint, both JM and MK would be the same.
Set the two equations to equal each other and dolve for x:
7x-32 = 89-4x
Add 32 to both sides:
7x = 121-4x
Add 4x to both sides:
11x = 121
Divide both sides by 11:
x = 121 /11
x = 11
Now you have a value for x, solve for MK:
MK = 89-4(11) = 89-44 = 45
The answer is A. 45
