2 2 121*m - 9*n
121*m^2 - 9*n^2 при m = 1/4
121*m^2 - 9*n^2
121*(1/4)^2 - 9*n^2
121/16 - 9*n^2
121.0*m^2 - 9.0*n^2
(-3*n + 11*m)*(3*n + 11*m)