I came across the following equation,
$f(t)=(1+2t)+(1-2t)u(t-1)+(3-2t)u(t-2)+(2t-5)u(t-3)$
Where $u(t-a)$ is a unit step (or Heaviside) function and it is defined as $u(t-a)=\begin{cases} 0&t<a\\1&t\geq a \end{cases}$
Now I have to plot $f(t)$ (in y-axis) vs $t$ (in x-axis). My confusion is in generating a expression for $f(t)$ in terms of $t$ alone by using appropriate expression for $u(t-1)$, $u(t-2)$, and $u(t-3)$. Can someone help me to get the correct plot?