(x - a) (x + y)=х^2+ху-ах+ау
(t + 8) (b + k)=tb+tk+8b+8k
(a + 2) (6-3)=6a-3a+12+6=3a+18=3(a+6)
(d - 4) (t + 5)=dt+5d-4t-20
(x - a) (x + y)=х^2+ху-ах+ау
(t + 8) (b + k)=tb+tk+8b+8k
(a + 2) (6-3)=6a-3a+12+6=3a+18=3(a+6)
(d - 4) (t + 5)=dt+5d-4t-20