Thread: Why some solutions of system of linear equations create contradictions?

Lets take a simple system of two equations:


after evaluating a_{1} from the first equation and putting it into the second we get


this gives

so, solutions are: q=1, q=-1 and q=

but if you try to put this into the original system of equations, only q= works, why?

thanks

You're first evaluation is incorrect... If you solve the first equation for you get:





Plug this into the second equation to get:









That's why the other answers don't work, because they are not solutions to the system.

<blushing> Thanks

No problem.