Matematika

Pertanyaan

Akar akar persamaan kuadrat (x+1)=36-x² adalah α dan β. Persamaan kuadrat baru yang akar akarnya (α+β-3) dan 2/5(αβ)) adalah..
Tolong sama caranya yaa hehehe

2 Jawaban

  • (x + 1) = 36 - x²
    x + 1 - 36 + x² = 0
    x² + x - 35 = 0

    alpha + beta = -b/a
    = -1/1
    = -1

    alpha . beta = c/a
    = -35/1
    = -35

    cari akar akar yg baru , misal x1 dan x2
    x1 = ( alpha + beta - 3)
    = (-1-3)
    = -4

    x2 = 2/5 (alpha.beta)
    = 2/5 (-35)
    = -14

    PK :
    x² - (x1+x2)x + (x1.x2) = 0
    x² - (-4+(-14))x + (-4.-14) = 0
    x² + 18x + 56 = 0
  • Matematika VIII SMP
    →→ Persamaan Kuadrat ←←

    Pembahasan :
    x + 1 = 36 - x²
    x² + x - 35 = 0

    Berdasarkan Teorema Vietta
    aβ = c/a
    aβ = -35

    a + β = -b/a
    a + β = -1

    Maka...
    x² - (a + β - 3 + 2/5aβ)x + (a + β - 3 . 2/5aβ) = 0
    x² - (-4 - 14)x + (-4 . (-14)) = 0
    x² + 18x + 56 = 0

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