Question

I need help. I didn't get a good teacher at school so I didn't understand this:
The table shows the outputs y for different inputs x:

Input
(x) 5 6 7 8
Output
(y) 2 5 8 11


Part A: Do the data in this table represent a function? Justify your answer.
Part B: Compare the data in the table with the relation f(x) = 2x + 13. Which relation has a greater value when x = 7?
Part C: Using the relation in Part B, what is the value of x if f(x) = 75?

Answer 1

Isn't it when x its own y?

Answer 2

I mean when x has its own y

Answer 3

hmm.. well the "formal" defintion of a function is that for every value of "x", there is ONLY one value of "y".
So basically, each "x" cannot have more than 1 y-value.
:) So do you think your data is a function?

Answer 4

Yes

Answer 5

excellent :D So now moving onto part b.
Look at the function given:
\[f(x) = 2x + 13 \]
What would f (7) = ?
[note: to do this, just plug in x = 7 ... basically replace the x with a 7 ]

Answer 6

2(7)+13
So 27?

Answer 7

yyees! :)
So for the relation f (x) = 2x + 13 , f (7) = 27

Now looking at your table, what is your "y" when x= 7 ?

Answer 8

8

Answer 9

yes, so now can you answer part b? :)

Answer 10

Yes

Answer 11

I think I can answer C too now

Answer 12

alrightiess :)

Answer 13

see, it wasn't as bad as you thought :)!

Answer 14

I guess it wasn't explained well by my algebra teacher. Thanks!

Answer 15

you're welcome :)!