1. diketahui f(x) = ax+b. Jika f(1)=3 dan f(2) = 4, maka f(x) 2. diketahui f(x) = ax + b, jika f(1) = 4 dan f(2) = 7, maka f(x)

Bab Fungsi
Matematika SMP Kelas VIII

1] f (x) = ax + b

    f (1) =   a + b = 3
    f (2) = 2a + b = 4
            ----------------- -
                    - a = -1
                      a = 1

a + b = 3
1 + b = 3
b = 3 - 1
b = 2

f (x) = x + 2

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2] f (x) = ax + b

    f ( 1 ) =   a + b = 4
    f ( 2 ) = 2a + b = 7
              ----------------- -
                      - a = -3
                        a = 3

a + b = 4
3 + b = 4
b = 4 - 3
b = 1

f ( x ) = 3x + 1