Сокращение,сложение и вычитание,упрощение дробей. Заранее спасибо)

Решите задачу:

$\displaystyle 1.a)..\frac{25c^{5}d^{4}}{30c^{4}d}= \frac{5}{6}cd^{3} \\ \\ 1.b).. \frac{t^{2}+t}{ t^{2}}= \frac{t(t+1)}{t^{2} }= \frac{t+1}{t} \\ \\ 1.c).. \frac{c+3d}{c^{2}-9d^{2}}= \frac{c+3d}{(c-3d)(c+3d)}= \frac{1}{c-3d} \\ \\ \\ 2.a).. \frac{4e}{e-f}- \frac{4f}{e+f}=\frac{4e(e+f)-4f(e-f)}{e^{2}-f^{2}}=\\\\=\frac{4e^{2}+4ef-4ef+4f^{2} }{e^{2}-f^{2}}=\frac{4(e^{2}+f^{2})}{e^{2}-f^{2}}\\\\2.b)..\frac{3-vw}{3v+vw}+ \frac{3w}{3+w}=\frac{3-vw+3vw}{v(3+w)}=\frac{3+2vw}{v(3+w)} \\ \\$

$\displaystyle 2.c)..f- \frac{f^{2}}{f+5}= \frac{f(f+5)-f^{2} }{f+5}= \frac{5f}{f+5} \\\\\\ 3).. \frac{6}{c^{2}-d^{2}}- \frac{8}{cd-c^{2}}-\frac{14}{c^{2}+cd}=\\\\= \frac{6}{(c-d)(c+d)}+ \frac{8}{c(c-d)}- \frac{14}{c(c+d)}=\frac{6c+8(c+d)-14(c-d)}{c(c-d)(c+d)}= \\\\=\frac{6c+8c+8d-14c+14d}{c(c-d)(c+d)}=\frac{22d}{c(c^{2}-d^{2} )} \\ \\ \\ 4).. \frac{fu-fv+6u-6v}{f^{2}-36}= \frac{f(u-v)+6(u-v)}{(f-6)(f+6)}= \frac{(f+6)(u-v)}{(f-6)(f+6)}= \\ \\ = \frac{u-v}{f-6}$

$\displaystyle u=4,1; v=2,8;f=6,1 \\ \\ \frac{u-v}{f-6}= \frac{4,1-2,8}{6,1-6}= \frac{1,3}{0,1}=13$