(х + 2)(х - 3) = 2х(х - 4) + 6

(x + 2)*(x - 3) = 2x*(x - 4) + 6
x^2 - 3x + 2x - 6 = 2x^2 - 8x + 6
2x^2 - 8x + 6 - x^2 + x + 6 = 0
x^2 - 7x  + 12 = 0
По  формуле  Виета  х1  =3,   х2  =  4