(x-5)(x-3)(x+8)(2x-4)=0

(x - 5)(x - 3)(x + 8)(2x - 4) = 0 2(x - 5)(x - 3)(x + 8)(x - 2) = 0 x-5 = 0    v    x-3 = 0    v    x+8 = 0    v     x-2 = 0 x = 5       v    x = 3       v    x = -8       v     x = 2 x ∈ {-8, 2, 3, 5}