Question

сократить дробь подробное описание, пожалуйста(x^2-81)/(9-x)^2

Answer 1

$\frac{ { {x}^{2} - 81} }{( {9 - x)}^{2} } = \frac{(x - 9)(x + 9)}{( {9 - x)}^{2} } = \frac{ - (9 - x)(x + 9)}{ {(9 - x)}^{2} } = - \frac{x + 9}{9 - x}$

Answer 2

$\frac{(x {}^{2} - 81) }{(9 - x) {}^{2} } \\ \\ \frac{(x - 9) \times (x + 9)}{( - (x - 9) )^{2} } \\ \\ \frac{(x - 9) \times (x + 9)}{(x - 9) {}^{2} } \\ \\ \frac{x + 9}{x - 9}$