Suatu fungsi di definisikan dengan rumus f(x)=ax+b,jika f(-2)=12 dan f(5)=15.Tentukan: a. Nilai a=..... Nilai b=..... b. Rumus Fungsinya=.... c Nilai dari f(-5

a.
f(x) = ax + b

f(-2) = -2a + b
-2a + b = 12

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

Eliminasi
5a + b = 15
-2a + b = 12
---------------- -
7a = 3
a = 3/7

5a + b = 15
5(3/7) + b = 15
15/7 + b = 15
b = 15 - 15/7
b = 105/7 - 15/7
b = 90/7

b. rumus fungsi
f(x) = ax + b
f(x) = 3/7 x + 90/7

c.
f(-5) = 3/7(-5) + 90/7
= -15/7 + 90/7
= 75/7