[tex] \sf3m + 12 = 15 \\ \sf3m = 15 - 12 \\ \sf3m = 3 \\ \sf \: m = \frac{3}{3} \\ \sf \: m \: = \underline{ \bf \: 1}[/tex]
-> Just move all the numbers from the left side to the right side until only the variable is left. Then you can solve the equation & find the required value.
