Question

7 клас, алгебра) очень срочно)

Answer 1

$a-\frac{2}{a}=-3\\\\(a-\frac{2}{a})^{2} =(-3)^{2}\\\\a^{2}-2*a*\frac{2}{a}+(\frac{2}{a})^{2}=9\\\\a^{2} -4+\frac{4}{a^{2} }=9\\\\a^{2}+\frac{4}{a^{2} }=9+4\\\\\boxed{a^{2}+\frac{4}{a^{2}}=13}$

Answer 2

$a-\frac{2}{a}=-3\Rightarrow \left(a-\frac{2}{a}\right)^2=(-3)^2;\ a^2-2a\cdot\frac{2}{a}+\left(\frac{2}{a}\right)^2=9;$

$a^2-4+\frac{4}{a^2}=9;\ a^2+\frac{4}{a^2}=13.$

Ответ: 13