6) 0.8(x - 2) + 2.6 = 0.5(7 + x)

0.8x - 1.6 + 2.6 = 3.5 + 0.5x => 0.8x - 0.5x = 3.5 - 1 => 0.3x = 2.5 => x = 2.5 / 0.3 ≈ 8.33