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?

please post question here - lots of members will not go to third party site to download

 

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?

 

Hint: the determinant of the system must not be zero

Well here is the answer SNIP gave me: 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

Edited June 5, 20223 yr by Phi for All
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On 2/23/2017 at 7:45 AM, foxsboris.naumov1994 said:

 

Well here is the answer SNIP gave me: 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

 

Did you look at the post just above yours?