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    2nd Year Functions Help joecole

    Can anyone help me with this question please?

    The function "f" is defined by f:x = 7-3x. If f(24) = kf (-2), find the value of k.

    Thanks.

    1. avatar image

      Cutclutc

      i think that the answer is k = 5

      f:x = 7-3x

      f(24) = 7-3(24)

      f(24) = 7-72

      f(24) = -65

      kf(-2) = k(7-3(-2))

      f(-2) = 13

      k = 65/13

      k = 5

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      joecole

      Thanks a million. That the answer in the marking scheme.

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      AssemblyRequired

      Just a question: if f(24)=-65, how come at the end k=65/13 (note the difference in sign).

    4. avatar image

      AssemblyRequired

      Here's how I worked it out:

      f(24)=7-72

      =-65

      kf(-2)=k(13)

      =13k

      -65=13k

      -65/13=13k/13

      -5=k

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      mossy_oc

      If you have a Casio calculator you can press mode 3 then put in the function and the range and it gives you the answer in a table

    6. avatar image

      mossy_oc

      If you're drawing a graph

    7. avatar image

      mossy_oc

      Of a function

    8. avatar image

      joecole

      Thanks, but it was just to solve for 'k'.

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      Me

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