Question

can someone help pls.
The table shows the outputs y for different inputs x:

Input
(x) 3 7 11 15
Output
(y) 4 6 8 10


Part A: Do the data in this table represent a function? Justify your answer. (3 points)
Part B: Compare the data in the table with the relation f(x) = 5x – 21. Which relation has a greater value when x = 11? (2 points)
Part C: Using the relation in Part B, what is the value of x if f(x) = 99? (5 points)

Answer 1

A. Yes because for every input, you have an output (?)

Answer 2

Because each input is related to exactly one output.

Answer 3

In Part B, you need to find the value of x first in 5x-21, do you know how to do that?

If you do, you'll just compare it and conclude your answer!

Answer 4

This is what i got for Part B: f(11)=5(11)-21 @ienarancillo

Answer 5

Ohh, I had a different way of understanding it :((

Answer 6

from what I understand,

there's this f(x) = 5x - 21 right? So, I guess you need to find x first

And that is ..?

Answer 7

honestly i have no idea im so confused.. @ienarancillo

Answer 8

just find x in 5x-21 :)

Answer 9

so its 34? because i plugged in the 11 for x

Answer 10

yeah, meaning that the function in part b has a greater value

Answer 11

as for C, plug in 99 for x

Answer 12

uhm wait a sec,

\[f(x)=y=5x-21\]

Answer 13

\[y=\frac{ 5x }{ 5 }=\frac{ 21 }{ 5 }\]

\[y=f(x)=\frac{ 21 }{ 5 } \approx 4.2\]

Answer 14

but looking at the table,

when x = 11 , y = 8

Answer 15

so comparing

y = 4.2
y = 8

I think you know it form here :)

Answer 16

but please correct me if I'm wrong bc this is how I understood the problem

Answer 17

im still confused :(

Answer 18

let's start from the top

Answer 19

oso we're given f(x)=5x-21 right?

Answer 20

^ from that given equation, do you know how to find x?

Answer 21

* guys please correct me if I'm wrong! :)

Answer 22

yeah i plugged in the 11 for x

Answer 23

Noo, if you plug in x, you'll get y. just dont mind the x=11 first, that's a different function

Answer 24

like y = 5(11)-21

You get y here! Not x! :)

Answer 25

do you get it?

Answer 26

yeaah

Answer 27

sooo transposing ..

we get \[5x = 21\]

Answer 28

and then, we want to find x so divide both sides by 5 \[\frac{ 5x }{ 5 } = \frac{ 21 }{ 5 }\]

Answer 29

so far so good?