Question

дам 15 баллов помогите. ​

Answer 1

Ответ: A.

$a = - 1$

$\frac{5 {a}^{9} - 3 {a}^{7} }{4 {a}^{8} } = \frac{5 \times {( - 1)}^{9} - 3 \times {( - 1)}^{7} }{4 \times {( - 1)}^{8} } = \frac{5 \times ( - 1) - 3 \times ( - 1)}{4 \times 1} = \frac{ - 5 - ( - 3)}{4} = \frac{ - 5 + 3}{4} = - \frac{2}{4} = - \frac{1}{2} = - 0.5$