X^2-5x+6-x^2+1-3x-7=0 -8x=0 x=0
(x-3) (x-2) - (x-1) (x+1) = 3x + 7. х^2-2х-3х+6-(х^2+х-х-1)=3х+7. х^2-5х+6-х^2-х+х+1=3х-7. -5х+6+1=3х+7. -8х=0. х=0