Question

Решите все эти задания

Answer 1

$2a)\; \frac{3x-1}{x^2}+\frac{x-9}{3x}=\frac{3(3x-1)+x(x-9)}{3x^2}=\frac{9x-3+x^2-9x}{3x^2}=\frac{x^2-3}{3x^2}\\\\2b)\; \frac{1}{2a-b}-\frac{1}{2a+b}=\frac{2a+b-(2a-b)}{(2a-b)(2a+b)}=\frac{2a+b-2a+b}{(2a)^2-b^2}=\frac{2b}{4a^2-b^2}\\\\4)\; \frac{2a}{a-5}-\frac{5}{a+5}+\frac{2a^2}{25-a^2}=\frac{2a(a+5)-5(a-5)-2a^2}{(a-5)(a+5)}=\frac{2a^2+10a-5a+25-2a^2}{(a-5)(a+5)}=\\\\=\frac{5a+25}{(a-5)(a+5)}=\frac{5(a+5)}{(a-5)(a+5)}=\frac{5}{a-5}$