a)2.x=1/5

x=1/5:2

x=1/10

b)-8/5+x=13/6x12/13

x=2+8/5

x=18/5

c)x.3/7.1/7=-3/8

x=-3/8:3/49

x=-49/8

d)-4/7x+7/5=1/8.-3/5

-4/7x=-3/40-7/5

x=-59/40:-4/7=413/160

 $x=7-\genfrac{}{}{0ex}{}{2}{5}+1,62=8,22$
b) $x=4\genfrac{}{}{0ex}{}{3}{5}+\genfrac{}{}{0ex}{}{1}{5}-\genfrac{}{}{0ex}{}{1}{2}=4\genfrac{}{}{0ex}{}{3}{10}$
c) $2x-x=\genfrac{}{}{0ex}{}{3}{5}+\genfrac{}{}{0ex}{}{4}{7}$
$x=\genfrac{}{}{0ex}{}{41}{35}$
d) $x=3\genfrac{}{}{0ex}{}{1}{2}-\genfrac{}{}{0ex}{}{5}{7}+\genfrac{}{}{0ex}{}{1}{13}-0.25$
$x=2\genfrac{}{}{0ex}{}{223}{364}$