X^2-9x+14=0
D=81-56=25
x1=7 x2=2
x^2-4x+4=(x-2)^ 2
значит
((x-7)(x-2))/(x-2)^ 2=(x-7)/(x-2)
3x^2+7.5x-27=6x^2+15x-54
3x^2+10.5x-13.5=6x^2+21x-27
6x^2+15x-54=0
D=225+1296=1521=39^2
x1=-15+39)/2=12 x2=-15-39=-27
(x+27)(x-12)
6x^2+21x-27=0
D=441+648=1089=33^2
x1=-21-33)/2=-27 x2=-21+33)/2=6
(x+27)(x-6)
((x+27)(x-12))/((x+27)(x-6))= (x-12)/(x-6)