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12 June, 17:56

What is the value of 4r^2-8 when r=3?

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Answers (2)
  1. 12 June, 19:01
    0
    28.

    Step-by-step explanation:

    Put r = - 3 and work it out:

    That would be 4 (3) ^2 - 8

    = 4 * 9 - 8

    = 36 - 8

    = 28.
  2. 12 June, 19:55
    0
    28

    Step-by-step explanation:

    So this means to replace the r you see in 4r^2-8 with 3.

    Let's do that:

    4 (3) ^2-8

    Now to simplify this just use pemdas or a calculator:

    4 (9) - 8 since 3^2 means 3*3=9

    36-8

    28
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