WILL FAN AND MEDAL HELPPPP

Which relation is a function?

A.
(6, 5), (1, 1), (6, 4)

B.
(0, 1), (2, 3), (2, 5)

C.
(8, –2), (–2, 5), (6, 0)

D.
(–2, 3), (–5, 9), (–5, 3)

Question

WILL FAN AND MEDAL HELPPPP

Which relation is a function?	
 
 A.
(6, 5), (1, 1), (6, 4)
 
 B.
(0, 1), (2, 3), (2, 5)
 
 C.
(8, –2), (–2, 5), (6, 0)
 
 D.
(–2, 3), (–5, 9), (–5, 3)

jim_thompson5910 · Answer

Notice how choice A has

(6, 5), (1, 1), (6, 4)

where the points (6,5) and (6,4) repeat the x value (6)


x = 6 corresponds to both y = 5 and y = 4 at the same time. The question is: which is it? If it was a function, then x can only correspond to exactly one y value at a time. 


So choice A is NOT a function because of this reason

jim_thompson5910 · Answer

Alternatively, you can graph the points. If you can draw a vertical line through any two points you plotted, then you do NOT have a function.