Answer:
[tex]9(b + 5) - 4b = \\ 9b + 45 - 4b = \\ 5b + 45 = b + 9[/tex]
[tex] \looparrowright \sf9(b + 5) - 4b[/tex]
[tex] \\ \\ [/tex]
[tex] \looparrowright \sf9b + 45 = - 4b[/tex]
[tex] \\ \\ [/tex]
[tex] \looparrowright \sf9b + 4b + 45 = 0[/tex]
[tex] \\ \\ [/tex]
[tex] \looparrowright \sf5b + 45 = 0[/tex]
[tex] \\ \\ [/tex]
[tex] \looparrowright \sf5b = - 45[/tex]
[tex] \\ \\ [/tex]
[tex] \looparrowright \sf \: b = - 45 \div 5[/tex]
[tex] \\ \\ [/tex]
[tex] \looparrowright \sf \: b = -9[/tex]
