Задание
Выполни действия
\(\cfrac{7m+n}{m^{2}-n^{2}}+\cfrac{1}{m+n}=\cfrac{7m+n}{(m+n)(m-n)}+\cfrac{1}{m+n}=\) [ ].
\(\cfrac{4}{x^2-4y^{2}}-\cfrac{1}{xy-2y^{2}}=\) [ ].
\(\cfrac{b}{b+9}-\cfrac{b^{2}}{b^{2}+18b+81}=\cfrac{b}{b+9}-\cfrac{b^{2}}{(b+9)^{2}}=\) [ ].
\(\cfrac{16y^{2}}{9x^{2}-24xy+16y^{2}}-\cfrac{4y}{3x-4y}=\) [ ].