jika a + b = 1, dan a² + b² = 5, maka a³ + b³ =
Matematika
zet03
Pertanyaan
jika a + b = 1, dan a² + b² = 5, maka a³ + b³ =
1 Jawaban
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1. Jawaban arsetpopeye
a + b = 1
a² + b² = (a + b)² - 2ab
5 = 1² - 2ab
2ab = 1 - 5
2ab = -4
ab = -2
a³ + b³ = (a + b)³ - 3ab (a + b)
= (1)³ - 3(-2) (1)
= 1 + 6
= 7