Jawaban:

Rumus fungsi → f(x) = 2x - 1

Nilai f(1) → 1

Nilai f(-2) → -5

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Penjelasan:

f(x) = ax + b

f(2) = a(2) + b = 3

f(2) = 2a + b = 3 .... pers. 1

. .

f(x) = ax + b

f(3) = a(3) + b = 5

f(3) = 3a + b = 5 .... pers. 2

Eliminasi untuk mendapat nilai b

2a + b = 3

3a + b = 5

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2a - 3a = 3 - 5

-a = -2

a = 2

Subtitusi nilai a = 2

2a + b = 3

2(2) + b = 3

4 + b = 3

b = 3 - 4

b = -1

Rumus fungsi

f(x) = ax + b

f(x) = 2x + (-1)

f(x) = 2x - 1

Nilai f(1)

f(x) = 2x - 1

f(1) = 2(1) - 1

f(1) = 2 - 1

f(1) = 1

Nilai f(-2)

f(x) = 2x - 1

f(-2) = 2(-2) - 1

f(-2) = -4 - 1

f(-2) = -5

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Detail Jawaban:

• Mapel : Matematika
• Kelas : 8
• Materi : Fungsi
• Kode kategorisasi : 8.2.2
• Kata kunci : Rumus f(x), Fungsi, Pemetaan

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