3.
a) -19,5(-0,5x + 3,4) + 7,2x = 9,75x - 66,3 + 7,2x = 16,95x - 66,3 = 16,95 * (-0,1) - 66,3 = -67,995
б) 13,2y - 4(-2,5y - 13,5) + 24 1/7 =
=13,2y + 10y + 54 + 24 1/7 = 23,2y + 78 1/7 = 23,2 * (-0,5) + 78 1/7 =
= -11,6 + 78 1/7 = -3/5 + 67 1/7 = -21/35 + 67 5/35 = -21/35 + 66 40/35 = 66 19/35
4. 14,7(-7,2 + (13 1/3) * y) = 4(19,2 - 5,2y)
-105,84 + 588y/3 = 76,8 - 20,8y |*3
588y - 317,52 = 230,4 - 62,4y
650,4y = 547,92
y = 2283/2710