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C3 - Functions question watch

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    Hi,

    I'm a bit stuck on this question and would really appreciate it if someone could help:

    The function f is defined by f:x=(2x+5)/3

    (the inverse function) f^(-¹)=(3x-5)/2

    Show that f(-¹)(3) (the inverse function of 3) is the solution of the equation
    f(x)=3

    Thanks!
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    The function f is defined by f:x=(2x+5)/3

    (the inverse function) f^(-¹)=(3x-5)/2

    Show that f(-¹)(3) (the inverse function of 3) is the solution of the equation
    f(x)=3


    well first....

    .....sub in x=3 into f^(-¹)=(3x-5)/2 so you get f^(-¹)(3) = 2

    .....and now just work out (2x+5)/3 = 3 is and show that it equals 2.

    so (2x+5) = 9

    2x = 9-5
    2x = 4
    x=2 and it works!!
 
 
 
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