x + 1/X = 5 then find X^3 + 1/X^3 = ?
Answers
Answered by
2
Answer:
Using formula (a+b)^3
Step-by-step explanation:
(X+1/X)^3 = X^3+1/X^3+3*X^2*(1/X)+3*X*(1/X^2)
=> 5^3 = X^3+1/X^3 + 3X + 3/X
=> 125 = X^3+1/X^3 + 3(X+1/X)
=> X^3+1/X^3 = 125-3(5) = 125- 15 =110
=> X^3+1/X^3 = 110
Hope this help you!
Answered by
0
Answer:
Using formula (a+b)^3
Step-by-step explanation:
(X+1/X)^3 = X^3+1/X^3+3*X^2*(1/X)+3*X*(1/X^2)
=> 5^3 = X^3+1/X^3 + 3X + 3/X
=> 125 = X^3+1/X^3 + 3(X+1/X)
=> X^3+1/X^3 = 125-3(5) = 125- 15 =110
=> X^3+1/X^3 = 110
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