Question

помогите #37 пжжжжжж 5 балов халява

Answer 1

$1) 2cdot6,7+8cdot7,6+8cdot2,4+2cdot3,3= \ =(2cdot6,7+2cdot3,3)+(8cdot7,6+8cdot2,4)= \ =2cdot(6,7+3,3)+8cdot(7,6+2,4)=2cdot10+8cdot10= \ =10cdot(2+8)=10cdot10=100 \ \ 2)3cdot5,2+7cdot9,3+7cdot10,7+3cdot14,8= \ =(3cdot5,2+3cdot14,8)+(7cdot9,3+7cdot10,7)= \ =3cdot(5,2+14,8)+7cdot(9,3+10,7)=3cdot20+7cdot20= \ =20cdot(3+7)=20cdot10=200$
$3)12cdot2,3+17,7cdot11+17,7cdot9+8cdot2,3= \ =(12cdot2,3+8cdot2,3)+(17,7cdot11+17,7cdot9)= \ =2,3cdot(12+8)+17,7cdot(11+9)=2,3cdot20+17,7cdot20= \ =20cdot(2,3+17,7)=20cdot20=400$