Question

FAN AND MEDAL
g(x)=2x^2-4x-5
find g^-1(-2).... the inverse of the function, then multiplied by -2

Answer 1

g(x) is not one-to-one function. How can you have inverse?

Answer 2

steps to find inverse function
First, replace with y.
Replace every x with a y and replace every y with an x.
Solve the equation from step 2 for y.


after you'll find inverse, substitute -2 for x and solve for y.

Answer 3

Chloe, are you sure it's multiplication by -2?
It looks like they want you to evaluate the inverse function at -2.

Answer 4

\[\large\rm g(x)=2x^2-4x-5\]\[\large\rm -2=2x^2-4x-5\]Solve for x :D

Answer 5

@zepdrix yes, I think that you're right. Thank you

Answer 6

I am waiting for some one explain me how to get inverse of g(x) without limit the interval. :)

Answer 7

So I replace all x for y and all y for x. Then solve for y where x= -2 ?

Answer 8

i'm still very confused

Answer 9

Normally, this g(x) gives you your y-coordinate.\[\large\rm g(x)=y\]When we take the inverse, yes we switch the x's and y's,\[\large\rm g^{-1}(y)=x\]They want us to find g inverse of -2,
this occurs when y=-2\[\large\rm g^{-1}(-2)=x\]If you undo this inversion,
going back to the original equation,\[\large\rm g(x)=-2\]You're simply setting your y, which is g(x), equal to -2,
and solving for x.

Answer 10

It's a little different than problems you've done previously.

You're not actually looking for the inverse function,
because, as lose stated, that wouldn't be possible.

Instead, we're dealing with some basic properties of the inverse to kind of.. sneak through this one :)

Answer 11

@zepdrix Ok, that i now understand. and i think i was able to get the answer by following the steps that @AlexandervonHumboldt2 gave me. I in fact got two answers: 2.58 and 0.58

Answer 12

Hmm, those values seem correct,
shouldn't they be negative though? >.<

Answer 13

Oh I mean, just the 0.58 should be negative :o
my bad.

Answer 14

You used Quadratic Formula? :0

Answer 15

yes the quadratic formula and yes, sorry, it was meant to be -0.58

Answer 16

Hmm, ya :) weird problem.