Odpowiedzi

2009-12-16T12:22:59+01:00
(6d-a)(d+3a)=6D2+18ad-ad-3a2= 6d2+17ad-3a2
(X-y)(X+y)=x2+xy-xy-y2= x2-y2
(3a-b)(a+b)=3a2+3ab-ab-b2= 3a2+2ab-b2
(5X-3y)(5X+3y)=25x2+15xy-15xy-9y2= 25x2-9y2