Question

if a²+ 1/a²=7, find a³+ 1/a³​

Answer 1

Answer:

your answer attacted in the photo

Answer 2

Answer:

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$a {}^{2} + \frac{1}{av} = 7$

$a {}^{2} + \frac{1}{av} + 2 = 9$

$= (a + \frac{1}{a} ) {}^{2} = 9$

$= a + \frac{1}{a} = ± 3$

$a {}^{3} + \frac{1}{a {}^{3} } = (a + \frac{1}{a} ) {}^{3} - 3(a + \frac{1}{a} )$

$= (3) {}^{3} - 3(3)$

$= 27 - 9$

$= 18$

Again , $a {}^{3} + \frac{1}{a {}^{3} } = ( - 3) {}^{3} - 3( - 3) \\ = - 27 + 9 \\ = - 18$