A polynomial $$f\left(x\right)\;=\;a_4x^4\;+\;a_3x^3\;+\;a_2x^2\;+\;a_1x\;-\;a_0$$ with all coefficients positive has

Which one of the following statements is NOT TRUE for a continuous time causal and stable LTI system?

An amplifier with resistive negative feedback has two left half-plane poles in its open-loop transfer function. The amplifier

A system described by the transfer function $$$H\left(s\right)=\frac1{s^3+\alpha s^2+ks+3}$$$ is stable. The constraints on $$\alpha$$ and k are,