Knowing that –3 is the root of P (x) = x³ + 4x² – ax + 1, calculate the value of a and mark the correct answer.

Question

Knowing that –3 is the root of P (x) = x³ + 4x² – ax + 1, calculate the value of a and mark the correct answer.

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Trúc Chi 3 years 2021-08-13T12:52:58+00:00 1 Answers 6 views 0

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    2021-08-13T12:54:03+00:00

    Answer:

    value of a is -3.33

    or in fraction -10/3

    Step-by-step explanation:

    If -3 is the root of P(x)

    then

    P(-3) = 0

    then we substitute -3 in place of x in the given equation

    P (x) = x³ + 4x² – ax + 1

    P (-3) = -3³ + 4*-3² – a(-3) + 1

    => 0 = -27 + 36  + 3a + 1

    => 0 = 10 + 3a

    => 3a = -10

    => a = -10/3 = -3.33

    Thus, value of a is -3.33

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