Please solve question 8 fast

D e a r s t u d e n t, x^{2} + \frac{1}{x^{2}} = 7 {(x - \frac{1}{x})}^{2} = x^{2} + \frac{1}{x^{2}} + 2 . x . \frac{1}{x} = 7 + 2 = 9 x - \frac{1}{x} = 3 n o w 7 x^{3} + 8 x - \frac{7}{x^{3}} - \frac{8}{x} = 7 x^{3} - \frac{7}{x^{3}} + 8 x - \frac{8}{x} = 7 (x^{3} - \frac{1}{x^{3}}) + 8 (x - \frac{1}{x}) u \sin g a^{3} - b^{3} = (a - b) (a^{2} + a b + b^{2}) = 7 (x - \frac{1}{x}) (x^{2} + \frac{1}{x^{2}} + . x . \frac{1}{x}) + 8 \times 3 = 7 \times 3 \times (7 + 1) + 24 = 21 \times 8 + 24 7 x^{3} + 8 x - \frac{7}{x^{3}} - \frac{8}{x} = 192 R e g a r d s

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