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Math Help - Question about functions

  1. #1
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    Question Question about functions

    Hi people!
    My name is John, I am beginner in this forum but could realize that you really help too much. So, I ask that you help me to solve a matter of a school work. They are 15 matters and there is one missing that I did not manage to solve. This is the question:

    If F is the real function of real variable, like F(2X+1)=X for all x, so, what is the result of 2F(X)+3?
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  2. #2
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    Quote Originally Posted by jhonyGrund View Post
    Hi people!
    My name is John, I am beginner in this forum but could realize that you really help too much. So, I ask that you help me to solve a matter of a school work. They are 15 matters and there is one missing that I did not manage to solve. This is the question:

    If F is the real function of real variable, like F(2X+1)=X for all x, so, what is the result of 2F(X)+3?
    Let y= 2x+1 so that x= (y-1)/2. Then "F(2x+ 1)= x" becomes "F(y)= (y-1)/2. Can you find 2F(x)+ 3 now?
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  3. #3
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    Quote Originally Posted by HallsofIvy View Post
    Let y= 2x+1 so that x= (y-1)/2. Then "F(2x+ 1)= x" becomes "F(y)= (y-1)/2. Can you find 2F(x)+ 3 now?
    I Did not yet manage to understand. Could you be a little less objective?
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  4. #4
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    Ok, I think I understood the question.
    Here is the question solved:
    f(2x + 1) = x
    f(2x) = x - 1
    f(x) = (x - 1)/2

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

    Thank you for help!
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