Question

Помогите! Вычислите:
1) 139·15+18·139+15·261+18·261
2) 125·48-31·82-31·43+125·83

Answer 1

1) 139·15+18·139+15·261+18·261=139*(15+18)+261*(15+18)=(15+18)(139+261)=
=33*400=13200
2) 125·48-31·82-31·43+125·83=125(48+83)-31(82+43)=125*131-31*125=
=125(131-31)=125*100=12500

Answer 2

1)139*(15+18)+261*(15+18)=4587+8613=13200
2)125*(48+83)-31*(82-43)=16375-1209=15166