Type the list of points $\left[\left[1\,2\right]\,\left[3\,7\right]\,\left[4\,-2\right]\right]$ 

Context Panel:
Curve Fitting≻Interactive Curve Fitting≻x (as variable)
     Splines≻ Degree of the spline: 1
     Plot
     On 'Done" return Plot
(See Figure A-9.8(b).)

Enter the list of points.

$L≔\left[\left[1\,2\right]\,\left[3\,7\right]\,\left[4\,-2\right]\right]$

Graph the polygonal line through the points.

$p_1≔\mathrm{plot}\left(L\,\mathrm{style}\=\mathrm{line}\right)\:$

Graph the points.

$p_2≔\mathrm{plot}\left(L\,\mathrm{style}\=\mathrm{point}\,\mathrm{symbol}\=\mathrm{solidcircle}\,\mathrm{symbolsize}\=20\right)\:$

Combine the graphs of the polygonal line and the points.

$\mathrm{plots}\left[\mathrm{display}\right]\left(p_1\,p_2\right)$