Matematika

Pertanyaan

persamaan kuadrat mempunyai akar akar
persamaan kuadrat mempunyai akar akar

2 Jawaban

  • 4x² - x - 5 = 0
    (x + 1) (4x - 5)
    x1 = -1 dan x2 = 5/4

    x1² = (-1)² = 1
    x2² = (5/4)² = 25/16

    x1 + x2 = -b/a
    1 + 25/16 = -b/a
    41/16 = -b/a ~~~~> berarti b = - 41 dan a = 16

    x1x2 = c/a
    1 x 25/16 = c/a ~~~~> berarti c = 25

    pers. baru = 16x² - 41x + 25 = 0

    #maaf jika salah semoga membantu
  • Mapel : Matematika
    Bab : Persamaan Kuadrat

    Diketahui :
    - 4x² - x - 5 = 0
    - Akar 1 = x₁
    - Akar 2 = x₂

    Ditanya :
    - Nilai x₁² + x₂² = ......?

    Penyelesaian :
    - Nilai x₁ dan x₂ :
    4x² - x - 5 = 0
    = 4x² + 4x - 5x - 5
    = 4x(x + 1)- 5(x + 1)
    = (4x - 5)(x + 1)

    x₁ :
    4x - 5 = p
    4x = 5
    x = 5/4

    x₂ :
    x + 1 = 0
    x = - 1

    - Persamaan Kuadrat Berakar x₁² dan x₂² :
    a. Akar 1 :
    x₁²
    = (5/4)²
    = 25/16

    x = 25/16
    16x = 25
    16x - 25 = 0

    b. Akar 2 :
    x₂²
    = (- 1)²
    = 1

    x = 1
    x - 1 = 0

    c. Persamaan Kuadrat :
    (16x - 25)(x - 1)
    = (16x × x) - (16x × 1) - (25 × x) + (25 × 1)
    = 16x² - 16x - 25x + 25
    = 16x² - 41x + 25

    16x² - 41x + 25 = 0

    Maaf Kalau Salah