18k^2+7y-7ky-18k=18k^2-18k+7y-7ky=18k(k-1)+7у(1-k)=18k(k-1)-7y(k-1)=(18k-7у)(k-1) (18*1/9-7*2/7)(1/9-1)=(2-2)(-8/9)=0
18k^2+7y-7ky-18k=18k^2-18k+7y-7ky=18k(k-1)+7у(1-k)=18k(k-1)-7y(k-1)=(18k-7у)(k-1)
(18*1/9-7*2/7)(1/9-1)=(2-2)(-8/9)=0