suatu fungsi dirumuskan f(x)=ax+b. jika f (-2)=14 dan f (3)=-1, nilai f (7)adalah tolong di bantu kak

f(x) = ax + b


f(-2) = -2a + b
14 = -2a + b......(1)
f(3) = 3a + b
-1 = 3a + b....... (2)

Eliminasi b (1) (2)
-2a + b = 14
3a + b = -1
________-
-5a = 15
a = 15/ -5
a = -3
Substitusi a = -3 ke (2)
3a + b = -1
3(-3) + b = -1
b = -1 + 9
b = 8

Maka fungsinya f(x) = -3x + 8

Ditanyakan f(7) = -3(7) + 8 = -21 + 8 = -13

Kategori: Matematika - Fungsi
Kelas: VIII SMP
Kata Kunci: spldv, nilai fungsi
Pembahasan:

f(x) = ax + b (fungsi linear)

f(-2) = ax + b
14 = -2a + b

f(3) = ax + b
-1 = 3a + b

-2a + b = 14
3a + b = -1
__________-
-5a = 15
a = -3

3a + b = -1
-9 + b = -1
b = 8

f(7) = ax + b
       = -3 (7) + 8
       = -21 + 8
       = -13