(4a-b) (a+4b)=

4a²+16ab-ab-4b²=4a²+15ab-b²

(4a-b) (a+4b)=4a²+16ab-ab-4b²= 4a²+15ab-4b²

(4a-b) (a+4b)=4a2<2 jest podniesione do kwadratu>-ab+16ab-4b2<2 jets podniesione do kkwadratu>. (4a-b) (a+4b)=4a2-ab+16ab-4b2= 4a2-16-4b2