Question

I'll Mark the best answer as brainiest
Plz give step by step answer
If a^2+1/a^2=18 and his not equal to 0 find a³-1/a³

Answer 1

First of all the question is unclear, you brackets are missing, I have no clue if you meant (a² + 1) / a² = 18 or a² + (1/a²) = 18 ,

17 a² = 1

a² = 1/17

a = 1/√17

So, a³ = 1/√17³

(a³-1)/a³ = 1 - 1/a³ = 1 - √17³

Or if you mean the other way,

$a^{4} + 1 = 18 a^{2}$

$a^{4} - 18a^{2} + 1 = 0$

a² = [18 ± √(324 - 4)] / 2

a = √(9 ± 4√5)

Since this gives logrithmninc answer I suppose your answer is 1 - √17³.

NEXT TIME PLEASE GIVE CLEAR QUESTION WITH BRACKETS, maths is magical and can have various meanings.