Question

Find f^-1(x) if f(x) = -4x - 2.

Answer 1

According to my tutor, the final answer is 4x - 2

Answer 2

I believe she is wrong, could someone verify this?

Answer 3

@Zarkon @kropot72 @goformit100 @ghazi

Answer 4

yeah, its incorrect.

Answer 5

let y= -4x-2
to get inverse function, we first replace 'x' by 'y' and 'y' by 'x'
so,
x = -4y-2
got this ?
now try to isolate (find) y from here.

Answer 6

x=-2?

Answer 7

So would it be x-2/4 ?

Answer 8

x = just -2 ?
x = -4y -2
add 2 on both sides, what u get ?

Answer 9

I got 2x=-4y

Answer 10

no no ...
x = -4y -2
x+2 = -4y -2+2
so, x+2 = -4y
got this ?

Answer 11

Got it

Answer 12

now, x+2 = -4y
so, multiplying -1 on both sides
-x-2 = 4y
just divide both sides by 4 and you'll get y

Answer 13

y= -1/2

Answer 14

you just won't get value of y
you'll get a function of 'x'
(-x-2)/4 = y
thats your f^-1(x) = -(x+2)/4

Answer 15

You're the best at explaining things @hartnn thankss!

Answer 16

hey thanks! :)
and welcome ^_^