Hello,

Could someone please tell me how to solve exercises 11, 22 and 26?

Exercise 11

The answer of exercise 11 should be that b is not a linear combination of a1, a2 and a3. I computed the echelon form of the augmented matrix where a1, a2, a3 and b are the columns of the augmented matrix, but I end up with a consistent system, so I don't understand why b is not a linear combination of a1, a2 and a3.

Exercise 22

Not even a clue where to start...???

Exercise 26

In 26(a) I found that the system is consistent, so b is in W. How do I solve 26(b)?

Thanks for your help!

Lotte