When cyclist squeezes her brake lever, she can stop with an acceleration of -3.0 m/s^2 how far will her bike travel while coming to a complete stop if her initial speed was 11 m/s

We shall use the formula
v² = u² + 2as
where
v =  final speed. v = 0 because the cyclist comes to a complete stop.
u = initial speed. u = 11 m/s, given
a = acceleration. a = -3.0 m/s², given
s =  distance traveled, m.

Therefore
0 = 11² + 2(-3.0)*s
0 = 121 - 6s

That is,
6s = 121
s = 121/6 = 20.167 m

20.2 m (nearest tenth)

You need to do x2-x1,y2-y1 and divide it by 2 and you should get (1,-3) 

The answer is 180ohohohoho