Anybody willing to help me with three easy questions please! I will fan and medal and love you forever <3

- anonymous

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- chestercat

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- anonymous

If h(x) = 4x − 8 and j(x) = −x, solve h[j(3)] and select the correct answer below.
A. −36
B. −20
C. 1
D. 4

- anonymous

a) what is \(j(3)\)?

- anonymous

J is -x and 3 is just 3.... wait are u asking me or are you confused? :)

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## More answers

- jim_thompson5910

satellite73 knows the answer
s/he is asking you to see if you know it

- anonymous

\[j(x)=-x\] so
\[j(\spadesuit)=-\spadesuit\] and \[j(\xi)=-\xi\] so what is \[j(3)\]?

- anonymous

Oh ok... Yes so I did 4x-8[-x(3)] but i keep getting 28

- anonymous

umm... -3?

- jim_thompson5910

j(3) is -3, yes

- anonymous

ok thanks

- anonymous

whew
b) what is \(h(-3)\)?

- jim_thompson5910

notice how satellite73 replaced the "j(3)" with "-3"
going from h[ j(3) ] to h(-3)
this only works because j(3) = -3

- anonymous

4x+24?

- jim_thompson5910

replace every x in h(x) = 4x − 8 with -3

- anonymous

oh ok so 4(-3) or -12 -8?

- anonymous

\[h(\diamondsuit)=4\times\diamondsuit-8\]\[h(\Phi)=4\times \Phi -8\]\[h(-3)+?\]

- jim_thompson5910

yeah just compute -12-8

- anonymous

-20

- jim_thompson5910

correct

- anonymous

omg tysm!!

- anonymous

I need help with 2 more... please

- jim_thompson5910

go ahead

- anonymous

Ray is purchasing a laptop that is on sale for 25% off. He knows the function that represents the sale price of his laptop is c(p) = 0.75p, where p is the original price of the laptop. He also knows he has to pay 8% sale's tax on the laptop. The price of the laptop with tax is f(c) = 1.08c, where c is the sale price of the laptop.
Determine the composite function that can be used to calculate the final price of Ray's laptop by solving for f[c(p)].
A. f[c(p)] = 1.83p
B. f[c(p)] = 1.83cp
C. f[c(p)] = 0.81p
D. f[c(p)] = 0.81cp

- jim_thompson5910

\[\Large f(c) = 1.08c\]
\[\Large f(\color{red}{c}) = 1.08\color{red}{c}\]
\[\Large f(\color{red}{c}) = 1.08(\color{red}{c})\]
\[\Large f(\color{red}{c(p)}) = 1.08(\color{red}{c(p)})\]
\[\Large f(\color{red}{c(p)}) = ??\]

- anonymous

um...

- jim_thompson5910

\[\Large f(c) = 1.08c\]
\[\Large f(\color{red}{c}) = 1.08\color{red}{c}\]
\[\Large f(\color{red}{c}) = 1.08(\color{red}{c})\]
\[\Large f(\color{red}{c(p)}) = 1.08(\color{red}{c(p)})\]
\[\Large f(\color{red}{c(p)}) = 1.08(\color{red}{0.75p})\]
\[\Large f(\color{red}{c(p)}) = ??\]
In the second to the last step, I replaced c(p) with 0.75p because c(p) = 0.75p

- anonymous

0.81

- jim_thompson5910

0.81p

- jim_thompson5910

don't lose the p

- jim_thompson5910

the c or c(p) goes away because it is replaced by 0.75p

- anonymous

oh ok got it so c right

- jim_thompson5910

yes

- anonymous

The following table shows the length and width of two rectangles:
Length Width
Rectangle A 2x + 8 x − 1
Rectangle B 3x + 5 2x − 2
Which expression is the result of the perimeter of rectangle B minus the perimeter of rectangle A?
A. 2x − 4
B. 8x + 10
C. 16x + 20
D. 4x − 8

- anonymous

Thank you! Last question

- jim_thompson5910

hint:
Perimeter = 2*(Length + Width)

- anonymous

ok so, 2*(2x+8)+(x-1) for the first one right?

- jim_thompson5910

2*[ (2x+8)+(x-1) ] actually

- anonymous

oh ok now what? when i simplify it i get 5x+15

- jim_thompson5910

you should get 2*(3x+7) = ???

- anonymous

ohh i see! ok so 6x+14?

- jim_thompson5910

yes, that is the perimeter of rect A

- jim_thompson5910

find the perimeter of rect B

- anonymous

so for rectangle B would be 2*[ (3x+5)+(2x-2) ]

- jim_thompson5910

yes

- jim_thompson5910

I'll be right back

- anonymous

ok

- anonymous

is the answer 10x+6

- jim_thompson5910

perimeter of rect A = 6x+14
perimeter of rect B = 10x+6

- jim_thompson5910

subtract the two perimeters

- anonymous

Well the directions say "perimeter of rectangle B minus the perimeter of rectangle A" but when i do that i get 4x+8 which is none of the options

- jim_thompson5910

10x - 6x = 4x ... correct
6 - 14 = 8 ... incorrect

- anonymous

Now I'm confused

- jim_thompson5910

B - A = (10x+6) - (6x+14) = 10x + 6 - 6x - 14 = ??

- anonymous

i got 4x+20

- anonymous

Did you mean to put 10x + 6 - 6x + 14 = ?

- jim_thompson5910

no the negative distributes through

- jim_thompson5910

- (6x+14) = -6x-14

- anonymous

oh ok so it would be the last one right?

- jim_thompson5910

yeah 4x-8

- anonymous

Thank you so much!!!!!!!!

- jim_thompson5910

no problem

- denisaboichuk

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