Question

Fungsi (f) ditentukan oleh f(x) =ax + b. Jika bayangan dari -3 adalah -15 dan bayangan dari 3 adalah 9.tentukan nilai dari f(-2) + f(2) !

Answer 1

Verified answer

F(-3) = a(-3) + b
-15 = -3a + b

f(3) = a(3) + b
9 = 3a + b

-15 = -3a + b
9 = 3a + b _
-------------------
-24 = -6a
24 ÷ 6 = a
4 = a

9 = 3(4) + b
9 = 12 + b
9 - 12 = b
-3 = b

f(-2) = (4)(-2) - 3
f(-2) = -8 - 3
f(-2) = -11

f(2) = (4)(2) - 3
f(2) = 8 - 3
f(2) = 5

f(-2) + f(2) = -11 + 5 = -6

Answer 2

Verified answer

Fungsi Linier

f(x) = ax + b

f(-3) = -15
-3a + b = -15 ... (1)

f(3) = 9
3a + b = 9 ... (2)

Kurangkan persamaan (1) dan (2)

(1) - (2) = -15 - 9
-3a - 3a = -24
-6a = -24
a = 4

3a + b = 9
3.4 + b = 9
b = -3

Fungsi :
f(x) = ax + b
f(x) = 4x - 3

▶ Nilai f(-2) + f(2)
f(-2) + (2)
= (4(-2) - 3) + (4.2 - 3)
= -6