Answer:
 [tex]B(-1) = 1\\\\B(3) = 0\\\\B(1) =2[/tex]  
Step-by-step explanation:
 By definition, a relation is a function if each input value has one and only one output value.
 The input values are the x-values and the output values are the y-values.
 Given:
 [tex]B(-1),B(3)[/tex] and [tex]B(1)[/tex]
 We can identify that we need to find the output values of these input values:
 [tex]x=-1\\x=3\\x=1[/tex] 
 Observe in the graph attached that:
-  When [tex]x=-1,\ y=1[/tex] 
-  When [tex]x=3,\ y=0[/tex] 
-  When [tex]x=1,\ y=2[/tex]  
 Therefore:
 [tex]B(-1) = 1\\\\B(3) = 0\\\\B(1) =2[/tex]