fungsi f dinyatakan dengan rumus f(x) = ax + b jika f(-5) = 15 dan f(5) = -5 nilai dari f(1) adalah

Kelas 8 Matemaatika
Bab Fungsi

f(x) = ax + b

f(-5) = -5a + b = 15
f(5) = 5a + b = -5

-5a + b = 15
5a + b = -5
------------------ + 
2b = 10
b = 5

5a + b = -5
5a + 5 = -5
5a = -5 - 5
a = -10/5
a = -2

f(x) = -2x + 5

f(1) = -2 . 1 + 5
f(1) = 3