Answer:
[tex]m = \boxed 7[/tex]
Combine like terms
[tex]21=33\cdot \mathrm{m}-21-27\cdot \mathrm{m}[/tex]
Group like terms
[tex]21=\left(33\cdot \mathrm{m}-27\cdot \mathrm{m}\right)-21[/tex]
Simplify the arithmetic
[tex]21=6\cdot \mathrm{m}-21[/tex]
Swap sides
[tex]6\mathrm{m}-21=21[/tex]
