Question

8 supra x la puterea 2 minus 9

Answer 1

$( \frac{8}{x} )$² - 9
= $(\frac{8}{x} )$² -3²
= $( \frac{8}{x} + 3)$ · $(\frac{8}{x} - 3)$
= $( \frac{8}{x} + \frac{3x}{x} ) * ( \frac{8}{x} - \frac{3x}{x} )$
= $\frac{3x+8}{x}$ * $\frac{8-3x}{x}$
= $\frac{(8+3x)(8-3x)}{x^{2} } = \frac{ 8^{2} - (3x)^{2} }{ x^{2} } = \frac{16-9 x^{2} }{ x^{2} }$