Consider the system S1: y(t) = 2x(t). is the system an LTI system? Justify your response b. What is the impulse response of this system? c. What is the output of this system if the input is x(t) = u(t - 2). d. If we consider a second system S2 defined by its impulse response hut) = -2, we put the two system in cascade. Express the overall impulse response h(t) of the cascade system