Matematika

Pertanyaan

fungsi f ditentukan oleh f(x) = ax+b . jika bayangan dr -3 adlh -15 dan bayangan dr 3 adlh 9, tentukan nilao dr f(-2)+f(2)

1 Jawaban

  • f(-3)=a(-3)+b
    -15=-3a+b

    f(3)=a(3)+b
    9=3a+b

    eliminasi
    (-3a+b=15)-(3a+b=9)
    -6a = -24
    a = 4

    substitusi
    3a+b = 9
    3(4)+b = 9
    12+b = 9
    b = -3

    f(-2) = a(-2)+b
    =4(-2) + (-3)
    = -8-3
    = -11

    f(2)= a(2)+b
    = 4(2)+(-3)
    = 8-3
    =5

    jadi f(-2)+f(2) = -11+5 = -6

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