$\displaystyle f(x)=\left\{\begin{array}{cc}2,&\mbox{if}x\leq -3\\2x+3, & \mbox{if}-3<x<0\\1, &\mbox{if}x\geq \end{array}\right.$

In This function How can i find the domain and Range of f(x)

should i go through the graph method or any other method.please explain how can i do this?