1) 7x - 28 - 7 = 8x - 32 => 7x - 35 = 8x - 32 => x = -3.
2) 6x - 42 + 13x = 14x - 42 + 27 => 19x - 42 = 14x - 15 => 5x = 27 => x = 5.4.
3) -4.55y + 20.65 = 6.8y - 11.13 => 11.35y = 31.78 => y ≈ 2.8.
4) 1.2z - 2.52 = 1.3z - 2.08 => 0.1z = -0.44 => z = -4.4.