2,4(b-0,6)+3,2(b-0,4)=4
2.4(b - 0.6) + 3.2(b - 0.4) = 4 2.4b - 1.44 + 3.2b - 1.28 = 4 5.6b = 4 + 2.72 5.6b = 6.72 b = 6.72 : 5.6 b = 1.2
2,4в-1,44+3,2в-1,28=4 5,6в-2,72=4 5,6в=6,72 в=1,2