Question

30.M-M dijawab beserta cara pengerjaan​

Answer 1

Jawaban:

Penyelesaian :

• f(x) = ax² + bx
• f(1) = -1
• f(2) = 2

Mencari rumus fungsi

f(x) = ax² + bx

f(1) = a(1)² + b(1) = -1

a + b = -1 ... (i)

f(2) = a(2)² + b(2) = 2

4a + 2b = 2 ... (ii)

• Eliminasi b

a + b = -1 |× 2| 2a + 2b = -2

4a + 2b = 2 |× 1 | 4a + 2b = 2 (-)

-2a = -4

a = -4/-2

a = 2

• Substitusi a

a + b = -1

(2) + b = -1

2 + b = -1

b = -1 - 2

b = -3

Maka rumus fungsi f(x)

f(x) = ax² + bx

f(x) = (2)x² + (-3)x

f(x) = 2x² - 3x

Maka jawabannya adalah f(x) = 2x² - 3x

'조슈아' (Svt)