8) 2ab - 8 - 6ab = -4ab - 8 = -4 * (ab + 2)
9)2(5a - 3b) - (a + 7b) = 10a - 6b - a - 7b = 9a - 13b
10)(a - 2b) - 3(a - 5b) = a - 2b - 3a + 15b = -2a + 12b = -2 * (a - 6b)
11)0.1(x + 2) + 0.2(x - 4) = 0.1x + 0.2 + 0.2x - 0.8 = 0.3x - 0.6 = 0.3(x - 2)
12)0.2(x - 1) + (2 - x) = 0.2x - 0.2 + 2 - x = -0.8x + 1.8
13)0.5(1 - 0.2x) - (x - 1) = 0.5 - 0.1x - x + 1 = -1.1x + 1.5
14)(3x - 4) - 0.5(2x + 2) = 3x - 4 - x - 1 = 2x - 5