12x^2 -(4x-3)(3x+1)= -2
12x² -(4x -3)(3x+1) = -2 ; 12x² -(12x² +4x -9x -3) = -2 ; 5x +3 = -2 ; 5x = -5 ; x= -1. * * * неинтересно * * *