Which representations are functions x y

2 6

3 -12

4 7

5 5

2 -6

(1,1 )

2,1

3.2

4.3

5.5

6.8

7,13

1V y=2x+1

A1 and 2

b 3 only

c 2 and 1V

d 1V only

Asource of laser light sends rays ab and ac toward two opposite walls of a hall. the light rays strike the walls at points b and c, as shown below: what is the distance between the walls?