Step-by-step explanation:
[tex]\qquad\sf {:}\longrightarrow m+\dfrac {1}{m}=3 [/tex]
[tex]\qquad\sf {:}\longrightarrow m^2+1/m=3 [/tex]
[tex]\qquad\sf {:}\longrightarrow m^2+1=3m[/tex]
[tex]\qquad\sf {:}\longrightarrow m^2-3m+1=0 [/tex]