Упрости выражения. 1) \dfrac{a+6}{18}+\dfrac{a-3}{9}= . 2) \dfrac{4n-1}{n}-\dfrac{4m-2}{m}= . 3) \dfrac{6-c}{4p}+\dfrac{c-3}{6n}= . 4) \dfrac{3b+2}{ab^2}-\dfrac{3a-5}{a^2b}= . 5) \dfrac{1}{c^3}-\dfrac{8+c^3}{c^6}= . 6) \dfrac{5}{m}+\dfrac{7m-5}{m-2}= . 7) \dfrac{9}{x}-\dfrac{9}{x+2}= . 8) \dfrac{b}{b-5}-\dfrac{5}{b+5}= . 9) \dfrac{y}{y+1}+\dfrac{4}{2y+1}= . :