The sum of the numbers a and b is 9, whereas their product is 20. Find
(i) a3
+ b3
(ii) a2
– ab + b2
Answers
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0
Answer:
1 . 189
2. 21
Step-by-step explanation:
using simple algebraic formulae
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Answered by
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Given : a+b = 9
a×b = 20
(a-b) ² = a²+b²-2ab
(9)² = a²+b² - 2(20)
81 +40 = a²-b²
121 = a²- b²
(a+b) ³ = a³+b³+3ab(a+b)
(9) ³ = a³+b³ + 3(20) (9)
729 = a³+b³ + 540
729- 540 = a³+b³
189 = a³+b³
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