Question

help with my answers corrections
medal plus fan .
Which of the following statements have the same result? Explain each step in solving each one.

I f(3) when f(x) = 2x + 2
II f-1(4) when f(x) = 3x minus 4, all over 5
III y + 10 = 2y + 1

Answer 1

I. f(3) when f(x)= 2x+2
f(x)=2x+2
f(3)=2(3)+2= 8

II. f^-1(4) when f(x)= 3x-4 all over 5
f(x)= 3x-4 all over 5
To find f^-1(x) just swap the variables to solve for x:
y= 3x-4 all over 5
swap variables:
x= 3y-4 all over 5
solve for x
5x=3y-4
5x+4= 3y
y= 5x+4 all over 3
f^-1(x)= 5x+4 all over 3
5*4= 20
20+4= 24
24/3= 8

III. y+10 = 2y+1
y+10= 2y+1
10= y+1
y= 9

I and II equals to 8, which for this question these functions has the same statements, while III equals to 9.

Answer 2

@sourwing

Answer 3

@ganeshie8

Answer 4

@Gokuporter

Answer 5

Looks great ! good job !!

Answer 6

okay im stuck on another 1 please help

Answer 7

okay

Answer 8

Emma wants to compare some cell phone plans by graphing their cost per text message. Mobilama charges a flat rate of $30 for unlimited texts. Celly-On-The-Go has no set-up charge, but it does charge $0.10 per text. Ringit Wireless only charges $0.05 per text, but it has an account charge of $15.

Explain to Emma how she can graph these cell phone plans and describe what key features of the graphs she should consider when making a decision.

Answer 9

setup the equations first

Answer 10

`Mobilama charges a flat rate of $30 for unlimited texts. `

\[y = 30\]

Answer 11

`Celly-On-The-Go has no set-up charge, but it does charge $0.10 per text. `
\[y = 0.1x\]

Answer 12

can you setup the equation for third plan ?

Answer 13

no, i think

Answer 14

did u get how the above two equations were setup ?

Answer 15

yehh

Answer 16

good, see if u can try and setup the third equation same way... give it a try :)

Answer 17

`Ringit Wireless only charges $0.05 per text, but it has an account charge of $15.`

Answer 18

kk

Answer 19

translate that word problem into an equation

Answer 20

can x be involved

Answer 21

say, x = number of texts

`Ringit Wireless only charges $0.05 per text,`

so cost of "x" texts would be : `0.05x`

Answer 22

ohh i see

Answer 23

but since they also charge a fixed account charge of $15,

the expression for total cost wud be : `0.05x + 15`

Answer 24

so the varyiabe would either be attached or equal to to the number

Answer 25

variable*

Answer 26

Here are the equations for `total cost` of each of 3 plans :

Mobilama : \(y=30\)
Celly : \(y = 0.1x\)
Right Wireless : \(y = 0.05x + 15\)

Answer 27

btw, the variable `y` represents "total cost"
the variable `x` represents "number of text messages"

Answer 28

graph them in geogebra and analyze them

Answer 29

you need to look for which graph stays low (that is less cost) and in what intervals (upto how many messages)

Answer 30

do u have geogebra on ur computer ?

Answer 31

no

Answer 32

http://www.geogebra.org/webstart/geogebra.html

Answer 33

this is my moms computer i cant

Answer 34

@ganeshie8

Answer 35

click that link,
u can graph it online

Answer 36

enter the equations in `Input` bar

Answer 37

i know but it says download and im not alllowed to download anything

Answer 38

okay @ganeshie8 i got it now what do i do, do i plug in the expressions that you taught me and try to find the lowest line

Answer 39

im lost on how to work this

Answer 40

@ganeshie8

Answer 41

@Preetha

Answer 42

can you help me

Answer 43

@whpalmer4 needd help please help

Answer 44

@blueweek77

Answer 45

yes ! graph them and get a feel of how the lines look first,
and see which line stays low..

Answer 46

i dont know how cuhz at the bottom i put in y= 30 and it went str8 to the side

Answer 47

it shows the graph on right side also

Answer 48

hold up i think i got it but whe im done can you look over my answers for this question

Answer 49

sure :)
u need to press `ctrl -`

(control minus)

Answer 50

to zoom out

Answer 51

once u graph all the 3 lines, analyze them a bit and attach the snapshot here ok ?

Answer 52

okay hold up

Answer 53

take ur time

Answer 54

@ganeshie8

Answer 55

Excellent ! now look at the lines, which plan is cheap ?

Answer 56

y=0.05x+15

Answer 57

think again

Answer 58

.01 right i misread it

Answer 59

whats the full equation ?

Answer 60

y=0.1x

Answer 61

and why is it cheap ? explain

Answer 62

you're right ! could u explain why do u think its the cheapest option ?

Answer 63

because unlike the others it starts in the middle but falls rapidly i think

Answer 64

All lines are rising up right ?

Answer 65

the y axis represents COST,
and the x axis represents number of text messages

Answer 66

As u text more, u need to pay more as well right ?

Answer 67

Notice that the \(\color{Red}{red}\) line has LOW value when u limit ur texts to `less than 300`

Answer 68

so thats the cheapest option for you if ur texts are `less than 300`

Answer 69

okay wid that ?

Answer 70

yes i jus have to add a little more to my answer then can you correct it

Answer 71

yes and think about which option is cheap if ur texts are more than 300

Answer 72

also u may write about which option is costly based on ur number of texts

Answer 73

Mobilama charges a flat rate of $30 for unlimited texts.
y= 30

Celly-On-The-Go has no set-up charge, but it does charge.
y= 0.1x

Ringit Wireless only charges $0.05 per text.
x= 0.05
but since they also charge a fixed account charge of $15, the expression for total cost would be : 0.05x+15

the total costs of each 3 plans would be:
Mobilama : y=30
Celly : y=0.1x
Right Wireless : y=0.05x+15

Basically when you do word problems x and y is built in the words. So in word y represents the "total cost" and x represents " number of text messages".

so on a graph y=0.1x would be the lowest line than the others, even though they all rise up, the more you text, they more they take, because your paying more money, so basically the others has high values and the only lowest value on the graph is y=0.1x.

Answer 74

@ganeshie8

Answer 75

y=0.1x is cheap only if ur texts are less than 300

Answer 76

look at the graph, zoom out and go to the far right when x = 300

Answer 77

the lines are crossing one another at that point

Answer 78

y = 0.1x is not longer low after x = 300, right ?

Answer 79

yehh there both at the same spot

Answer 80

after x it rises just like the others
ohh i see hold up

Answer 81

so on a graph y=0.1x would be the lowest line than the others, even though they all rise up, the more you text, they more they take, because your paying more money, but at the reaching point of 300 ( on graph ), y=0.1x is no longer the lowest line after x=300.

Answer 82

so is this the problem @wolf1728

Answer 83

@zzr0ck3r

Answer 84

What exactly do you mean "Is this the problem"?

Answer 85

nvm about that 1 can you help with this 1

Answer 86

Megan and Julie are stuck simplifying radical expressions. Megan has to simplify the quantity of x to the one third power, over x to the one twelfth power. Julie has to simplify the thirty second root of the quantity of x times x to the second times x to the fifth. Using full sentences describe how to fully simplify Megan and Julie’s expressions. Describe if Megan and Julie started with equivalent expressions or if they started with expressions that are not equal.

Answer 87

pleasee

Answer 88

Well I might have to make a graphic to avoid:
x^1/3/x^1/12
that sort of thing.

Answer 89

you can do anyhing you want, :) i just want to the right answer and learn at the same time

Answer 90

Okay here's the problem (I think)

Answer 91

So, is Julie's calculation supposed to be the 32nd root of x^20 ?