Question

на фото будь ласка п​

Answer 1

Объяснение:

8.

$(\frac{3}{x+3} +\frac{x^2+9}{x^2-9} -\frac{3}{3-x} )*\frac{x-3}{x^2+6x+9}=(\frac{3}{x+3} +\frac{x^2+9}{(x+3)(x-3)} +\frac{3}{x-3} )*\frac{x-3}{x^2+6x+9}=\\=\frac{3*(x-3)+x^2+9+3*(x+3)}{(x-3)(x+3)}*\frac{x-3}{x^2+6x+9}= \frac{3x-9+x^2+9+3x+9}{(x-3)(x+3)}*\frac{x-3}{x^2+6x+9}=\\=\frac{x^2+6x+9}{(x-3)(x+3)}*\frac{x-3}{x^2+6x+9}=\frac{1}{x+3}.$

9.

$x+\frac{1}{x}=5\ \ \ \ \ \ \ \ x^2+\frac{1}{x^2} =?\\ (x+\frac{1}{x})^2=5^2\\x^2+2*x*\frac{1}{x} +\frac{1}{x^2}=25 \\x^2+2+\frac{1}{x^2}=25\\x^2+\frac{1}{x^2}=23.$