Matematika

Pertanyaan

suku banyak f(x) dibagi (x-2) sisa 1, dibagi (x+3) sisa -8. Suku banyak g(x) dibagi (x-2) sisa 9, dibagi (x+3) sisa 2. jika h(x) = f(x).g(x), maka sisa pembagian h(x) dibagi x2 + x - 6 adalah ?

2 Jawaban

  • Materi: Suku banyak

    f(x) = (x-2)H(x) + 1 f(2) = 1
    f(x) = (x+3)H(x)-8 f(-3)=-8
    g(x) = (x-2)H(x)+9 g(2) = 9
    g(x) = (x+3)H(x)+2 g(-3) = 2

    h(x) = (x+3)(x-2)H(x)+ax+b
    h(2) = f(2).g(2) = 9 = 2a+b
    h(-3) = f(-3).g(-3) = -16 = -3a+b
    Eliminasi b shg diperoleh
    25 = 5a, a = 5, akibatnya b = -1
    Jadi sisa pembagiannya adalah 5x-1.
  • f(x) : (x - 2) sisa 1 => f(2) = 1
    f(x) : (x + 3) sisa -8 => f(-3) = -8

    g(x) : (x - 2) sisa 9 => g(2) = 9
    g(x) : (x + 3) sisa 2 => g(-3) = 2

    h(x) = f(x) . g(x)
    h(2) = f(2) . g(2) = 1 . 9 = 9
    h(-3) = f(-3) . g(-3) = -8 . 2 = -16

    h(x) : (x^2 + x - 6) misalkan bersisa (ax + b)
    x^2 + x - 6 = (x - 2)(x + 3) => x = 2 atau x = -3
    h(2) = 2a + b = 9
    h(-3) = -3a + b = -16
    --------------------------- -
    ............ 5a = 25 => a = 5

    2a + b = 9 => 2(5) + b = 9 => b = -1

    Sisa = ax + b = 5x - 1

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