For #2, most people argue that since lambda1 not equal lambda2,  then it's 
impossible to have
equivalence between (lambda1*v1+lambda2*v2) and  (lambda3(v1+v2))
however, this is true only when v1 and v2 are independent.
A simple counter example for the false logic is:
suppose v1 and v2 are dependent,  say v2=2v1
then 2v1+1/2*v2=1*(v1+v2)   is true

----------------------------------------
 Many people lost a mark on  question 5 for not showing that lambda does not 
equal zero.
----------------------------------------------------