3ft per second on a still sidewalk (27/9) , 11ft on the moving sidewalk.(99/9)
Hope this helps!
Easy peasy
the midpoint between

and

is

just average them
so given that (3,5) is the midpoint of (-4,5) and (x,y)

so by logic

and

times both sides by 2 for everybody
-4+x=6 and 5+y=10
add 4 to both sides for left one and minus 5 from both sides for right
x=10 and y=5
the coordinate of point C is (10,5)
the x coordinate is 10
Step-by-step explanation:
= -4 + 12 + (-9)
= -4 + 12 - 9
= -4 + 3
= -1