jawablah soal berikut dengan tepat
Matematika
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Pertanyaan
jawablah soal berikut dengan tepat
1 Jawaban
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1. Jawaban whongaliem
g (x) = x² - x + 3 ; (f o g ) (x) = 3x² - 3x + 4
(f o g) (x) = 3x² - 3x + 4
f (g (x)) = 3x² - 3x + 4
f (x² - x + 3) = 3x² - 3x + 4
misal : x² - x + 3= A
x² - x = A - 3
x² - x + 1/4 = A - 3 + 1/4
(x - 1/2)² = (4A - 11) / 4
x - 1/2 = √{(4A - 11) / 4}
x - 1/2 = 1/2 √(4A - 11)
x = 1/2 + 1/2 √(4A - 11)
x = 1/2 (1 + √(4A - 11)
soal menjadi :
f (A) = 3 {1/2 (1 + √(4A - 11)}² - 3 {1/2 (1 + √(4A - 11) + 4
f (x - 2) = 3 {1/2 (1 + √{4(x - 2) - 11)}² - 3 {1/2 (1 + √{4(x - 2) - 11} + 4
= 3 {1/2 (1 + √(4x - 8 - 11)}² - 3 {1/2 (1 + √(4x - 8 - 11) + 4
= 3 {1/2 (1 + √(4x - 19)}² - 3{ 1/2 (1 + √(4x - 19)} + 4
= 3 {1/4 (1 + 2√(4x - 19) + 4x - 19) - 3/2 - 3/2√(4x - 19) + 4
= 3/4 + 3/2 √(4x - 19) + 3x - 57/4 - 3/2 - 3/2 √(4x - 19) + 4
= 3/4 + 3x - 57/4 - 3/2 + 4
= 3x + (3/4 - 57/4 - 6/4 + 4)
= 3x - 60/4 + 4
= 3x - 15 + 4
= 3x - 11 .... jawaban : E