Question

If a³+1/a³ = 52 , then the value of 2(a+ 1/a) is
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Answer 1

Step-by-step explanation:

a³ + 1/a³ = 52

a³ + 1/a³ + 3(a+1/a) = 52 + 3(a+1/a)

( a + 1/a)³ = 52 + 3( a + 1/a)

(a + 1/a)³ - 3(a+1/a) - 52 = 0

a + 1/a = 4 is satisfying above polynomial.

on putting a + 1/a = 4

4³ - 3(4) - 52

64 - 12 - 52 = 0

So , the value of 2(a + 1/a ) = 2*4 = 8