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Решите задачу:

$\frac{3x-1}{x^2} - \frac{x-9}{3x} = \frac{3(3x-1)-x(x-9)}{3x^2} = \frac{9x-3-x^2+9x}{3x^2} = \frac{-x^2+18x-3}{3x^2} =-\frac{x^2-18x+3}{3x^2}$

$\frac{1}{2a-b} - \frac{1}{2a+b} = \frac{(2a+b)-(2a-b)}{(2a-b)(2a+b)} = \frac{2a+b-2a+b}{4a^2+2ab-2ab-b^2} =\frac{2b}{4a^2-b^2}$

$\frac{5}{c+3} - \frac{5c-2}{c^2+3c} = \frac{5}{c+3} - \frac{5c-2}{c(c+3)} = \frac{5c-(5c-2)}{c(c+3)} =\frac{5c-5c+2}{c(c+3)} =\frac{2}{c^2+3c}$