Question

СРОЧНО! МАТЕМ 10КЛАСС. 10БАЛЛОВ!

Answer 1

$a^2+\frac{9}{a^2}=22\\\\\\(a-\frac{3}{a})^2=a^2-2\cdot a\cdot \frac{3}{a}+\frac{9}{a^2}=a^2-6+\frac{9}{a^2}=(a^2+\frac{9}{a^2})-6=22-6=16\, ;\\\\\star \; \; \; x^2=A\; \; \Rightarrow \; \; \; x=\pm \sqrt{A}\; \; \; \star \\\\a-\frac{3}{a}=\pm 4\\\\Otvet:\; \; D)\; .$