Thank you for your answer. I am new to this site.
But what I do not understand is why my studybook gives as echelon form the form with the "a-4/3" and Mathematica gives with RowReduce something without the a ????.
Where is the "a" in Mathematica now ? I do not understand what Mathematica is doing ? Can you help me ?
Best regards
A.Geeraert
