Respuesta :

naǫ
[tex]6+\frac{4}{5}b=\frac{9}{10}b \ \ \ |-\frac{4}{5}b \\ \\ 6=\frac{9}{10}b-\frac{4}{5}b \\ \\ 6=\frac{9}{10}b-\frac{8}{10}b \\ \\ 6=\frac{9-8}{10}b \\ \\ 6=\frac{1}{10}b \ \ \ |\times 10 \\ \\ b=60[/tex]