А) 2,5:1,5=2 1/2:1 1/2=5/2:3/2=5/3=1 2/3
б) 2 3/4:1 1/2=11/4:3/2=11/6=1 5/6
1.
1) 5/8 + 11/36=20/36 + 11/36 = 31/36
2) 31/36 * 6/67 = 31/402
2.
1) 3/8 * 5 = 15/8
2) 4 1/6 * 2 1/10 = 25/6 * 21/10 = 105/12
3) 9/20 * 6 = 54/20 = 2,7
4) 15/8 + 105/12 = 60/36 + 315/36 = 375/36
5) 375/36 - 27/10 = 1875/180 - 486/180 = 1389/180 = 7 43/60
AC = ( -1-0; 3-4) = (-1;-1).
AB = ( -3-0; 5-4) = (-3; 1).
AC - 2*AB = (-1;-1) - 2*(-3;1) = (-1;-1) - (-6;2) = ( -1-(-6);-1-2) = (5;-3).