Given:
The system of equation is


To find:
Whether (3,4) is a solution of the given system or not.
Solution:
We have,
...(i)
...(ii)
Putting the value of y in (ii) from (i), we get




Divide both sides by -7.


Putting
in (i), we get




So, the only solution of the given system is
.
Hence, (3,4) cannot be a solution of given system, Hence the correct option is B.