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? asked in Education & ReferenceHomework Help · 7 years ago

math question involving inverses!!!?

how do you find the inverse of

f(x) = (x +3)/(x-2)

i thought i wouldn't be able to find the inverse of this because there would be 2 y's, but the back of the book had the inverse!

4 Answers

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  • ?
    Lv 6
    7 years ago

    Make it y=(x +3)/(x-2)

    Swap the x and y

    x = (y +3)/(y-2)

    Now solve for y

    x(y-2)=y+3

    xy-2x=y+3

    xy-y=2x+3

    y(x-1)=2x+3

    y=(2x+3)/(x-1)

  • ?
    Lv 6
    7 years ago

    The inverse function of: f(x) = (x +3)/(x-2) is:

    __________________________________________

    f ˉ¹(x) = (2x + 3) / (x-1)

    ________________________________________________

    There are, in fact, two (2) "y" variables, but there is, in fact, an inverse function. Here is how to find it:

    __________________________________________________________________________________

    Given: f(x)= y = (x +3) / (x-2) '

    _________________________________

    1) Re-write by switching the "y" variables to "x"; and the "y" variables to "y"

    ___________________________________________________________________

    (By the way, the symbol for the "inverse function" is: f ˉ¹(x) .

    ___________________________________________________________________

    x =(y+3) / (y-2) ---> Now we want to isolate the ["new"] y-value:

    ________________________________________

    x*(y-2) = y+3 ----? xy - 2x = y + 3 ---> Now, add "2x" to EACH side of the equation; Subtract "y" from each side of the equation: ----> xy - 2x + 2x -y = y + 3 - y + 2x

    -----> xy -y = 2x +3 ---> Now , we takes steps to further isolate "y":

    Factor out a "y" on the ';left-hand side"---and rewrite:

    y(x-1) = 2x +3 ----> Now, we can further isolate the "y", by dividing EACH side of the equation by "(x-1)":

    [y(x-1)]/ (x-1) = (2x + 3) / (x-1) ; to get:

    y = (2x + 3) / (x-1)

    ____________________________

    So, the inverse function of f(x) = (x +3)/(x-2) is:

    f ˉ¹(x) = (2x + 3) / (x-1)

    ____________________________________________

    {Note: f ˉ¹(x) is the symbol used to represent the inverse function}.

    ____________________________________________________________________

    Hopefully, this information is of some help to you.

  • david
    Lv 7
    7 years ago

    y = (x +3)/(x-2)

    x = (y + 3)/(y - 2)

    xy - 2x = y + 3

    xy - y = 3 + 2x

    y(x - 1) = 3 + 2x

    y = (3 + 2x)/(x - 1)

  • ?
    Lv 5
    7 years ago

    x = (y+3)/(y-2)

    xy-2x = y+3

    Can you do it from there?

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