1:1/2=1/1*2/1=2
1/7:8=1/7:8/1=1/7*1/8=1/56
1:8/11=1/1:8/11=1/1*11/8=1 3/8
AB = (1-(-2), -2-3, 3-1) = (3,-5,2)
BC = (4-1, -1-(-2), 0-3) = (3,1,-3)
2AB+3BC = 2*(3,-5,2) + 3*(3,1,-3) = (6,-10,4) + (9,3,-9) = (15,-7,-5)
|2AB+3AB| = sqrt (225 + 49 + 25) = sqrt (299)
3 целых 1/2 * 4/7 - 2 = 7/2 * 4/7 - 2 = 2 - 2 =0
1)8570-5935=2635(кг)-третий завод.
2)8570-5349=3221(кг)-первый завод.
3)8570-(2635+3221)=2714(кг)-второй завод.