this question was recently posted...look in this category.
If you are asking if there exist invertible matrices A and B such that , then we can easily say there does not. Use determinants.
However I think you dont know determinants and thats why they have given a 2x2 exercise. So it is the same as saying, AB = 2BA, Now write down the matrices 4 variables and equate the matrices term by term. This will show you that A or B cant be invertible.