(2.1)Examples of parametrised cubics.Some plane cubic curves can be parametrised, just as the conics:

Nodal cubicis the image of the map given by

Cuspidal cubic. is the image of given by

(1) Let Show that a varible line though meets at one further point, and hence deduce the parametrisation of given in (2.1). Do the same for and

If anyone could show me how to do any of those in (1), I would really appreciate it.. I have no idea how to tackle this problem. Thanks!