Matematika

Pertanyaan

jika f(x+5)=x²+2x+1 maka f(3)

1 Jawaban

  • Bab Fungsi
    Matematika SMP Kelas VIII

    f(x + 5) = x² + 2x + 1 
    f(x - 5 + 5) = (x - 5)² + 2 (x - 5) + 1
    f(x) = x² - 10x + 25 + 2x - 10 + 1
    f(x) = x² - 8x + 16

    f(3) = 3² - 8 . 3 + 16
    f(3) = 9 - 24 + 16
    f(3) = 1

    atau

    x + 5 = 3
    x = 3 - 5
    x = -2

    x² + 2x + 1 = (-2)² + 2 . (-2) + 1
                      = 4 - 4 + 1
                      = 1

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