Question

ok i am completely throw for a loop with this one please help Let f(x) = 12 over the quantity of 4 x + 2 Find f(-1).

Answer 1

to get f(-1) , just plug in x=-1 in f(x)
what do u get ?

Answer 2

it is like a fraction im so confused

Answer 3

then lets take the denominator only!
4x+2
put x=-1
what do u get ?

Answer 4

3+2

Answer 5

4(-1) means 4 is multiplied by -1
so, 4*(-1) =... ?

Answer 6

3

Answer 7

no -3 i mean

Answer 8

no...
4-1 =3
but not 4*(-1)

Answer 9

what is 4*1 = ... ?

Answer 10

4

Answer 11

yes, so
4*(-1) = - 4*1 = ... ?

Answer 12

4

Answer 13

so it should b -4

Answer 14

yes

Answer 15

so,
4x+2 = -4+2 = ... ?

Answer 16

-2

Answer 17

yes,
so f(-1) = 12/(-2) = -12/2 = ... ?

Answer 18

oh ok so i should just like move the minus sign

Answer 19

-6

Answer 20

thats correct!
f(-1) = -6 :)

Answer 21

ok i got it now tyvm

Answer 22

welcome ^_^

Answer 23

can u help me with one more please

Answer 24

Let f(x) = x2 - 81. Find f-1(x).

Answer 25

x^2 and the f^-1

Answer 26

i completely forgot how to do exsponents

Answer 27

so we take
y= x^2-81
interchange 'x' and 'y' to get

x = y^2 -81
now can you try to isolate y from this ?

Answer 28

good god my brain hurts lol

Answer 29

start by adding 81 on both sides

Answer 30

so it would look like 81x=y^2-81

Answer 31

no...

Answer 32

you know what is "adding" ?

Answer 33

yes i know how to add

Answer 34

ok, so adding 81 to x will give you
x+81
right ?

Answer 35

yes

Answer 36

so it would b 81x

Answer 37

no...81x means multiplying x with 81

Answer 38

oh ok

Answer 39

so just x+81

Answer 40

x+81 = y^2
take square root on both sides

Answer 41

how do i get into sq roots

Answer 42

the only number that i know that relates to 81 is 9

Answer 43

\(y^2= x+81

\\ y=\sqrt{x+81}\)
thats it!

Answer 44

ok stupider question how did u make sq root sign on puter

Answer 45

here ?
i wrote a code `\(\sqrt{...}\)`
\(\sqrt{...}\)

Answer 46

in my answer list this is there is this rt ±square root of the quantity x plus 81

Answer 47

yes, when you take square root, you need to consider both + and -

Answer 48

or is it one of theses 9square root of x

1 over quantity x squared minus 81

x squared over 81

Answer 49

its this
\(\pm \sqrt {x+81}\)

Answer 50

i gonna have to get my kid to figure out how to put that code in on my laptop

Answer 51

ok yes thats it exactly the way it looks on the answer thingy tysssvm

Answer 52

welcome :)