Answer:
x⁴ + 3x³ + 4x² + 12x = 0
<=> x³(x + 3) + 4x(x + 3) = 0
<=> (x³ + 4x)(x + 3) = 0
<=> x(x² + 4)(x + 3) = 0
6.5m questions
8.6m answers