Question

-2x(x+1)(x-4)(x2-16)<_0

Answer 1

-2x(x+1)(x-4)(x²-16)≤0    |÷(-2)
x(x+1)(x-4)(x-4)(x+4)≥0
x(x+1)(x-4)²(x+4)≥0
-∞___-___-4___+___-1___-___0__+__[4]__+__+∞
x∈[-4;-1]U[0;+∞).