MATRECIES: Suppose : R3 →R2 is the linear transformation that maps e1 to 2e′1 +e′2, e2 to e′1 +2e′2 and e3 to 3e′1 +e′2, where e1,e2,e3 are the standard unit vectors in R3 and e′1,e′2 are the standard unit vectors in R2. Find all values of that make onto.