Question

If a = -√35, then the value of a² - 1/a² is:
(a) 2 ( 6 + √35 )²
(b) 4 ( 6 + √35 )²
(c) -24√35
(d) 24√35

Answer 1

$a = - \sqrt{35} \\ {a}^{2} - \frac{1}{ {a}^{2} } \\( { - \sqrt{35} }) ^{2} - \frac{1}{ (- { \sqrt{35} })^{2} } \\ 35 - \frac{1}{35} \\ = \frac{1225 - 1}{35} \\ = \frac{1224}{35}$