Matematika

Pertanyaan

jika di ketahui akar akar dari persamaan kuadrat 2x^+mx+16=0 adalah alfa dan beta. jika alfa=2beta dan alfabeta posotif,maka berapakah nilai m??

2 Jawaban

  • Persamaan ²

    2x² + mx + 16 = 0

    alfa + beta = -b/a = -m/2
    alfa . beta = c/a = 16/2 = 8

    alfa + beta = -m/2
    2beta + beta = -m/2
    3beta = -m/2
    6beta = -m
    beta = -m/6


    alfa . beta = 8
    2beta.beta = 8
    2beta² = 8
    beta² = 4
    beta = 2 (krn positif)

    -m/6 = 2
    -m = 12
    m = -12
  • 2x^2 + mx +16 =0
    Akar2nya = alfa dan beta
    [tex] \alpha = 2 \beta \\ maka \\ \alpha \beta = \frac{c}{a} \\ 2 \beta \times \beta = \frac{16}{2} \\ 2 { \beta }^{2} = 8 \\ \ { \beta }^{2} = \frac{8}{2} =4 \\ \beta = 2 \: diambil \: yg( + ) \\ \\ \alpha = 2 \beta = 2 \times 2 = 4 \\ \\ \alpha + \beta = \frac{ -b}{a} \\ 4 + 2 = \frac{ - m}{2} \\ 6 = \frac{ - m}{2} \\ - m = 6 \times 2 \\ m = - 12[/tex]

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