UKH

Slightly desperate posting this here but have seen similar posts and responses previously... Ageing dude trying to get to grips with the CAS setup on Geogebra (the Classic 5 version, if that is worth anything). Simultaneous equations seemed more intuitive with the drag and drop, but I cannot find how/where to plot for example (-1,-3) and (2, 3) to churn out y = 2x - 1 using just CAS. 

Unfortunately I am without a book, and (unbelievably) my online searches haven't turned up anything resembling this. Thanks if anyone can sling me a hint!  

Do you want specifically to find the equation of a line through two given points? Or know how to do that in Geogebra?

if the former then you can use

y-y1=m(x-x1)

where m=(y2-y1)/(x2-x1)

I’ve just typed 

Line((-1,-3),(2,3))

into CAS Calculator app on IOS and it’s output y=2x-1 and plotted the line.

is that what you wanted?

Thank you very much, had to tinker a bit with the commands in the Geogebra version of CAS but that is showing equations of the form y = mx + c.