2 3/7 + 14/19 + 5 4/7 + 5/19 = (2 3/7 + 5 4/7) + (14/19 + 5/19) = 7 7/7 + 19/19 =
8 + 1 = 9
2 5/18 + 4/81 + 3 7/18 + 4 5/81 = (2 5/18 + 3 7/18) + (4/81 + 4 5/81) = 5 12/18 + 4 9/81 = 5 6/9 + 4 1/9 = 9 7/9
3 5/11 + 1 3/16 + 2 5/16 + 4 6/11 = (3 5/11 + 4 6/11) + (1 3/16 + 2 5/16) = 7 11/11 + 3 8/16 = 8 + 3 1/2 = 11 1/2
(5т794кг +781ц)×26=
50ц794кг+781ц=831ц794 кг
831ц794кг ×26=21266ц644кг =212т66ц644кг
/-0.63/:/x/=/-0.9/
0.63:/x/=0.9
/x/=0.63:0.9
/x/=0.7
x=0.7 и x=-0.7