АВD - развернутый
=> ABD = 180°
DBC = ABD - ABC = 180° - 54° = 126°
3/10 = 300г
5/100= 50 г
3/4= 750г
<span>3/5= 600г</span>
<span>1)-2,4a * (-5b)==12ab
2)9a-a-8b+3b=8a-5b
3)a+(a-10)-(15+a)=a+a-10-15-a=-25-a
4)-4(b-4)+7(b+2)=-4b+16+7b+14=3b+30
(3,25-(-1,75)) : (-0,6)+0,8*(-7)
</span>3,25-(-1,75)=3.25+1.75=5
5:(-0.6)=5*(-5.3)=-25/3
0.8*(-7)=-5.6
-25/3+(-5.6)=-25/3-28/5=-125/15-84/15=-209/15=-13 14/15