Linear Algebra Conditions

[Guest]

http://imgur.com/a/xIydC
The answers is b) ab≠1, but I have no clue how to get to that answer... Can someone help me?

[Guest]

Well as http://domyhomeworkfor.me/ solved it this can easily be done with determinants. If a square matrix's determinant does not equal zero, then that square matrix will have an inverse hence having a unique solution. Since this is a 2x2 matrix, just compute the determinant with the condition that it cannot equal zero:
(1)(2)-(2ab) =/= 0
2 =/= 2ab
1=/= ab

[Guest]

Do these websites also take your tests for you? Any intelligent teacher will base grades far more on exams than on homework. The purpose of homework is (1) for practice and (2) letting your teacher know where you need help. Having someone else do the work for you robs you of both.