Question

Determine whether the relation is a function. {(-7, -7), (-7, -8), (-1, 4), (6, 5), (10, -1)}

Answer 1

@jim_thompson5910 can you help?

Answer 2

@timo86m can you help?

Answer 3

I have about 3 questions i need help with

Answer 4

am i supposed to graph it myself?

Answer 5

dont plot

Answer 6

well if you a visual learner plot.

Answer 7

Its not a function i plotted some of them but to me i kind of determined it wasnt

Answer 8

if you get something like that then it is not a function.

what it means if you get to ys for one x

Answer 9

like say that x is one. so if you get like

1,2 and 1,3 or really 1,a where a is anynumber.

Answer 10

if at any time you have a x value that belongs to different y values it is not a function
you have
(7,-7) and (-7,-8) thus not a function

Answer 11

so i was correct its not.

Answer 12

(-7,-7) and (-7,-8) thus not a function*

Answer 13

right away you can tell that happens cuz x at -7 gets 2 y values

-7 and - 8

(-7, -7), (-7, -8)

Answer 14

thats what i thought because -7 & -7 doesnt work thats how i determined it..

Answer 15

Use the graph of y = f(x) to graph the given function g.

g(x) = -2f(x)

Answer 16

A.

Answer 17

B.

Answer 18

C.

Answer 19

D.

Answer 20

another way to think of it is if you grap a pencil and hold it vertically to the graph and move it left to right and your pencil doesn't touh twice 2 points then it is a function.

Answer 21

the rule -2f(x)

means flip it vertically and i think stretch vertically by factor of 2.

Answer 22

im confused..

Answer 23

I hate to get you back to the last problem but I don't think you understood why
"thats what i thought because -7 & -7 doesnt work thats how i determined it.."
what does not work about (-7,-7)?

Answer 24

because they are both negatives?

Answer 25

its not the point(-7,-7) that makes this thing not a function its the two points
(-7,-7) and (-7,-8)

Answer 26

no that has nothing to do with it

Answer 27

do you see how on those two points(-7,-7) and (-7,-8) they share a x values but the y values are different?

Answer 28

noo erin
Every x must have only one ploted point.

Answer 29

oh okayy i see what your saying now. I got it thanks !

Answer 30

as for secont q the rule is the original graph is flipped up and down. ANd shrinked by a factor of 2 i think.

Answer 31

@timo86m can you help me finish my second problem and i need help with one more thing can you go to wolfram and graph \[y = -\frac{ 1 }{ 2 }x-6\] and copy the url and post it on here because im not grasping the concept of how to do it

Answer 32

So for the second question I think I can elimante C and D.

Answer 33

NOtice how it intercepts the y axis at -6

y=mx+b
= -1/2 x -6
m b

b is where you start at the y axis.
-1/2 means you go down 1 and over 2.. then draw a line from the -6 to that point the down one over 2 and connect with a line.

Answer 34

m=rise / run

rise over run. Or if it is negative downward/ run.

Answer 35

the graph you just drew is that for the second question or my 3rd one?

Answer 36

for the y= = -1/2 x -6

Answer 37

So it would look like this

Answer 38

& can you still help me with my second question??

Answer 39

Yes that is how it looks like. You begin by putting a point at y axis at -6 then go down 1 over 2 cuzz your m is -1/2

Answer 40

okay so i got the right graph? & @timo86m can you help me with the second question?

Answer 41

yes i can :)

Answer 42

btw which is the f(x) graph the dotted line or solid line? does it say on your paper or online class or something?

Answer 43

Hey i already figured that one out. can you help me with one more.
Find the inverse of the one-to-one function.

Answer 44

\[f(x)=\frac{ 2x+5 }{ 7 }\]

Answer 45

inverse just means solve for x :)

Answer 46

A. \[f ^{-1}(x) = \frac{ 7 }{ 2x-5 }\]
B. \[f ^{-1}(x)=\frac{ 7x+5 }{ 2 }\]
C. \[f ^{-1}(x)=\frac{ 7x-5 }{ 2 }\]

Answer 47

im not understanding how to solve it

Answer 48

y=f(x)=(2x+5)/7

y=(2x+5)/7
solve for x

7y=2x+5 multiply both side by 7

7y-5=2x subtrac 5

(7y-5)/2=x

sway variables

y=(7x-5)/2

Answer 49

treat y as f^-1(x)