There are two ways to find out if two vectors are parallel in GeoGebra. One is simply to solve the vector equation  in CAS. The other is to draw two lines and use a GeoGebra command to check if they are parallel.                                                                                                                                                                                                                                          
     GeoGebra Instruction 1
Algebra     View     and         Graphics     View     under         View     in         Menu.         Algebra     View.         <first vector> = k * <second vector>
in CAS. Be sure to fill in your vectors with the names they are given in Algebra     View. Click Solve .         
      
     GeoGebra Instruction 2
Algebra     View     and         Graphics     View     in         View     menu.         Algebra     View.         Line(<point>, <direction vector>)
in Input Bar. Fill in (0,0) for <point> and one of the vectors for <direction     vector>. Press Enter. The line should now be shown Algebra View and         Graphics View.         
AreParallel(<line>, <line>)
in Algebra View. Input your two lines into the fields and press Enter. If true is         displayed in Algebra View, the vectors are parallel. If false is displayed in         Algebra View, the vectors are not parallel.