1. The problem statement, all variables and given/known data For what value(s) of a are the following vectors v1=[1,2,-1], v2=[0,1,3], and v3=[a,4,5] linearly dependent? 2. Relevant equations Since linear dependence means that any one of the vectors can be expressed as a linear combination of the other vectors: sv1v1+s2v2=v3 where s1and s2 are some coefficients. 3. The attempt at a solution Looking at the vectors, I tried v1+2v2=v3 Solving, I get a=1 I'm fairly certain I did the question correctly. The only thing that really bothers me is the plural of "value" in the question - is there ever a case where there can be more than one solution? How can I tell and solve those cases?