ditentukan rumus fungsi f(x)=ax + b,jika f(3)=14 dan f(-2)=-11

f(3) = 3a + b = 14
f(-2)=-2a + b = -11
______________ -
5a = 25
a = 5
b = -1
f(x)= 5x-1

Kelas 8 Matematika
Bab 2 - Fungsi

f(x) = ax + b

f(3) = 3a + b = 14
f(-2) = -2a + b = -11

Eliminasi nilai b
3a + b = 14
-2a + b = -11
_________ _
5a = 25
a = 25/5
a = 5

Substitusikan nilai a
3a + b = 14
3(5) + b = 14
15 + b = 14
b = 14 - 15
b = -1

Maka nilai
a = 5
b = -1

f(x) = ax + b
f(x) = 5x - 1