(0.5а - 0.6b + 5.5) - (- 0.5а + 0.4b) + (1.3b - 4.5) =
0.5а - 0.6b + 5.5 + 0.5а - 0.4b + 1.3b - 4.5 =
0.5а + 0.5а - 0.6b - 0.4b + 1.3b + 5.5 - 4.5 = a + 0.3b + 1.
(6у+2)(5-у) = 47-(2у-3)(3у-1)
30y-6y²+10-2y = 47-(6y²-2y-9y+3)
30y-6y²+10-2y = 47-6y²+2y+9y-3
30y-6y²-2y+6y²-2y-9y = 47-3-10
17y = 34
y = 2
Ответ : 2.