Linear System

$S(a{x}_1+b{x}_2)=aS(x_1)+bS(x_2)$

In other words, a system is linear if two conditions are met:

$S(ax)=aS(x)$

• The system is homogeneous

$S(x_1+x_2)=S(x_1)+S(x_2)$

• The system is allows superposition