Question

F(x)=ax+b,f(-5)=-3 dan f(1)=-9 tent rumus fungsinya

Answer 1

Mapel = Matematika

Kelas = VIII SMP

Materi = Fungsi

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Penyelesaian:

f (x) = ax + b
• f (- 5)
= - 5a + b = - 3 ......... (1)

• f (1)
= a + b = - 9 ............ (2)

✏Eliminasi b
- 5a + b = - 3
a + b = - 9
_________ _
- 6a = 6
a = 6/- 6
a = - 1

✏Substitusi a
a + b = - 9
- 1 + b = - 9
b = - 9 + 1
b = - 8

✏Rumus fungsi
f (x) = ax + b
f (x) = - 1x + (- 8)
f (x) = - x - 8

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Semoga Membantu ^^

Answer 2

f(x) = ax + b

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

-5a + b = -3

f(1) = a.(1) + b = -9

a + b = -9

a = -9 - b

Disubtitusi :

-5a + b = -3

-5.(-9 - b) + b = -3

45 + 5b + b = -3

45 + 6b = -3

6b = -3 - 45

6b = -48

b = -8

a + b = -9

a + (-8) = -9

a = -9 + 8

a = -1

f(x) = -x-8