Question

Fungsi f ditentukan dengan rumus f(x) = ax + b. Jika f(5) = 13 dan f(-2) = -8, tentukan nilai a dan b!

Answer 1

F (5) = 5a + b = 13
f (-2) =-2a + b = -8
        = 7a = 21
        = a = 21/7 = 3
f (5) = 5(3) + b = 13
       = 15 + b = 13
       = b = 13-15 = -2

jadi, a = 3, b = -2

Answer 2

F(x) = ax + b
f(5) = a5 + b
13 = 5a + b
13 - 5a = b

f(-2) = -2a + b
-8 = -2a + b
-8 + 2a = b

-8 +2a = 13 - 5a ( karna keduanya hasilnya b)
2a + 5a = 13 + 8
7 a = 21
a. = 3

b = 13 - 5a
b = 13 - 5x3
b = -2