[tex]3x+ \frac{4}{5}= \frac{7}{10}\ \ | -\frac{4}{5}\\ \\3x+ \frac{4}{5} -\frac{4}{5}= \frac{7}{10}-\frac{4}{5}\\ \\3x = \frac{7}{10}-\frac{8}{10} \\ \\3x = -\frac{1}{10} \ \ /*\frac{1}{3}\\ \\x=-\frac{1}{30}[/tex]
[tex]or \\ \\ \frac{3x+ 4}{5}= \frac{7}{10} \ \ /*10 \\ \\ 2(3x+4)=7\\ \\6x+8 = 7\ \ |-8[/tex]
[tex]6x+8-8=7-8\\ \\6x=-1\ \ /:6 \\ \\ x=-\frac{1}{6}[/tex]