if x+1/x=7 then find the value of x^3+1/x^3
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x³ + 1/x³ = (x+1/x)(x²-2+1/x²)
(x+1/x)² = x²+1/x² + 2
x²+1/x² = (x+1/x)² -2 = 49 - 2 = 47
x³ + 1/x³ = (x+1/x)(x²-2+1/x²) = 7 ( 47-2) = 7(45) = 315
(x+1/x)² = x²+1/x² + 2
x²+1/x² = (x+1/x)² -2 = 49 - 2 = 47
x³ + 1/x³ = (x+1/x)(x²-2+1/x²) = 7 ( 47-2) = 7(45) = 315
Ambika94:
well the answer is 322.
You have done a mistake it should be -1 in the first line not -2
Answered by
0
value is 343 (7^3)....
its 322
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