. Which relation is a function?

(Points : 4)
{(1, 2); (2, 3); (3, 4); (1, 5)}
{(1, 2); (2, 5); (3, 2); (4, 5)}
{(1, 2); (2, 3); (3, 4); (2, 5)}
{(1, 2); (1, 3); (3, 2); (4, 2)}

Question

. Which relation is a function?

(Points : 4)
       {(1, 2); (2, 3); (3, 4); (1, 5)}
       {(1, 2); (2, 5); (3, 2); (4, 5)}
       {(1, 2); (2, 3); (3, 4); (2, 5)}
       {(1, 2); (1, 3); (3, 2); (4, 2)}

jdoe0001 · Answer

that set that has NO X-REPEATS
"x" meaning the 1st number that is, in each pair of course

mathstudent55 · Answer

If in any choice you see the same x-coordinate more than once, it is not a function.

cwrw238 · Answer

relations which have 2 or more pairs  with a different second element for same fisrt element are not functions  eg {1,2), (1,3) (2,5)}   is not a function  because of the (1,2) and (1,3)

anonymous · Answer

so it would be B

cwrw238 · Answer

yes

mathstudent55 · Answer

Correct.

anonymous · Answer

What is the range of the relation?

{(1, 2), (2, 4), (3, 2), (4, 6)} 

(Points : 4)
       {1, 2, 3, 4}
       {1, 2, 3, 4, 6}
       {2, 4, 6}
       {2, 4}

mathstudent55 · Answer

The range of a relation is the set containing all the y-coordinates of the relation.

cwrw238 · Answer

the range is the set of the  second  (y) values

anonymous · Answer

so C

anonymous · Answer

/

anonymous · Answer

?

cwrw238 · Answer

yep - notice the 2 is not repeated

mathstudent55 · Answer

Correct.

anonymous · Answer

or the function f(x) = 2 − 3x, find f(−4). 

(Points : 4)
       −10
       −5
       12
       14

mathstudent55 · Answer

Replace x in 2 - 3x with -4 and evaluate.

mathstudent55 · Answer

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