7,3a-4-2,9a-7=4,4a-11; 8,2x+1,2-3,7x-2,7=4,5x-1,5; -7,9a-3,7-8,2+5a= -2,9a-11,9.
7,3a-4-2,9a-7 = (7,3a-2,9a) -(4+7) = 4,4а-11
8,2x+1,2-3,7x-2,7 = (8,2x-3,7x)+(1,2-2,7) = 4,5х+(-1,5) = 4,5х-1,5
-7,9a-3,7-8,2+5 = -7,9a-(3,7+8,2-5) = -7,9а-(6,9) = -7,9а-6,9
