Same as any other midpoint of line segment or two points, it is the average of the two points x and y coordinates...
mp=((x1+x2)/2, (y1+y2)/2)
mp=((-6+16)/2, (-9+5)/2)
mp=(10/2, -4/2)
mp=(5, -2)
Move all the terms involving the sine to one side, and all the numbers to the other:

The difference would be 0.27
Answer:
Step-by-step explanation:
1) corresponding angles
2)alternate interior angles
3)alternate interior angles
4)corresponding angles
2x-7=123
2x=130
x=65
5)corresponding angles
6x-11=5x
6) alternate interiot
40=14-2x
26=-2x
-13=x