Question

Kak tlg jawab ini jg ya..

tolonggggg

Answer 1

Verified answer

F(x) = ax² + bx + c
f(1) =>a + b + c = 0
b = -a - c

f(3) =>9a + 3b + c = 0
9a + 3(-a - c) + c = 0
6a - 2c = 0
2c = 6a
c = 3a

b = -a - c
b = -a - 3a
b = -4a

= -(b² - 4ac) / 4a
1 = (-b² + 4ac) / 4a
4a = -b² + 4ac
4a - 4ac + b² = 0
4a - 4a(3a) + (-4a)² = 0
4a - 12a² + 16a² = 0
4a + 4a² = 0
4a(1 + a) = 0

a = 0 (ditolak) atau a = -1

c = 3a
c = -3

b = -a - c
b = -(-1) - (-3)
b = 4

f(x) = -x² + 4x - 3

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Cara menggambar grafik

1. Grafik memotong sumbu x jika f(x) = 0

-x² + 4x - 3 = 0 (kali -1)
x² - 4x + 3 = 0
(x - 1)(x - 3) = 0
x = 1 atau x = 3
(1 , 0) dan (3 , 0)

2. Grafik memotong sumbu y jika x = 0
-(0)² + 4(0) - 3 = -3

(0 , -3)

3. Pers. Sumbu Simetri
x = -b/2a
=>-(4) / 2(-1) = 2

3. Titik baliknya adalah (Sumbu simetri , )
Maka titik baliknya (2 , 1)

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