Question

Find ‘k’ so that, the pair of the equations 2x + ky = 5; 7x – 5y = 11 has unique solution​

Answer 1

The equation are

2kx+5y−7=0

6x−5y−11=0

Here, a  

1

​  

=2k,b  

1

​  

=5,c  

1

​  

=−7

and a  

2

​  

=6,b  

2

​  

=−5,c  

2

​  

=−11

Forthesystemtohaveuniquesolution

⇒  

a  

2

​  

 

a  

1

​  

 

​  

 



=  

b  

2

​  

 

b  

1

​  

 

​  

 

⇒  

6

2k

​  

 



=  

−5

5

​  

 

⇒2k



=−6⇒k



=−3  

Answer 2

Answer:

:-k is not equal to -10/7