0.8*(3x-14)-0.3*(4-5x)=2.4x-11.2-1.2+1.5x=3.9x-12.4
если х=3целых1/13=40/13, то 3,9*40/13 - 12,4 = 12 - 12,4 = -0,4
Ответ: -0,4
8х = 3х - 15
8х - 3х = -15
5х = -15
х = -15 : 5
х = -3
A = {1; 3; 5; 7; 9}
B = {1; 2; 3; 4; 5; 6; 7; 8; 9; 10; 11; 12; 13; 14; 15; 16; 17; 18; 19; 20}
C = {10; 20; 30; 40; 50; 60; 70; 80; 90}
-27/20×(-5/9)-5/24×(-22/5) =1 2/3
1)-27/20×(-5/9)=27×5/20×9=3/4
2)-5/24×(-22/5)=5×22/24×5=11/12
3)3/4+11/12=9/12+11/12=20/12=5/3=1 2/3