Question

Calcule.
(4a+2b).(4a-2b)=
(2a+b).(2a-b)=
(5a+3b).(5a-b)=
(-6a+2b).(6a-2b)=
(7a+b).(7a-b)=
(a+2b).(a-2b)=
(9a+3b).(9a-3b)=

Answer 1

(4a+2b).(4a-2b)= 4a²-2b²=16a²-4b²
(2a+b).(2a-b)= 2a²-b²= 4a²-b²
(5a+3b).(5a-3b)=5a²-3b²=15a²-9b²
(-6a+2b).(6a-2b)= -6a²-2b²=36a²-4b²
(7a+b).(7a-b)=7a²-b²=49a²-b²
(a+2b).(a-2b)= a²-2b²=a²-4b²
(9a+3b).(9a-3b)=9a²-3b²=81a²-9b²