原式={[(2m-1/3)(3k^2+1)]/(3k^2+1)]}-[(2m-14/3)](3k^2+1)]+m^2
=(2m-1/3)-[(6m-14)/3](3k^2+1)]+m^2
=(2m-1/3)-[(6m-14)]/3(3k^2+1)]+m^2
=m^2+2m-1/3-[(6m-14)]/3(3k^2+1)]
原式={[(2m-1/3)(3k^2+1)]/(3k^2+1)]}-[(2m-14/3)](3k^2+1)]+m^2
=(2m-1/3)-[(6m-14)/3](3k^2+1)]+m^2
=(2m-1/3)-[(6m-14)]/3(3k^2+1)]+m^2
=m^2+2m-1/3-[(6m-14)]/3(3k^2+1)]