Question

cant determine which is a function:
A. {(5, 3), (8, –2), (8, 5), (–2, 8)}
B. {(5, 3), (3, 8), (5, –2)}
C. {(5, 3), (3, 5), (–2, –2)}
D. {5, 3, 8, –2}

Answer 1

in a function.. for each value of x there is one unique value for y

in option A.. for x=8 we have two values for y -2 and 5
so it is not a function
same in B.. there two values for y when x=5

C is a function

D is just a 4dimentional point so not a function

Answer 2

functions are pairs of numbers. But, the pairs can not have the same first number.
so (2,1), (2,3) is not a function (first number used more than once)

but
{ (1,2), (3,2) } is a function. first number is not re-used in any pair.

Answer 3

so a?

Answer 4

look at (a). Look at the 2nd and 3rd pair. Do they start with the same number? If so, it is NOT a function

Answer 5

its not a function so would u say b?

Answer 6

look at (b). look at the 1st pair and the last pair

Answer 7

it looks like none of them besides c and that doesnt really look like it would work either

Answer 8

what is wrong with c?

Answer 9

it just doesnt look right

Answer 10

reusing the first number is not allowed, but the 2nd number can be repeated.
{(5, 3), (3, 5), (–2, –2)}

Better get better specs. It looks good. Pairs of numbers, the first number in each pair are 5,3,-2 (no repeats). So it is a function.

Answer 11

D looks wrong because it is not a list of pairs.

Answer 12

so it is c?

Answer 13

Yes. Be more confident. You know the rules: is it a list of pairs. YES. Are there no repeats of the first number? YES. We have a function.

Answer 14

thanks alot :)