Question

9. The pair of linear equations 7x-3y=4,3x+k/7y=4
is consistent only when k=
​

Answer 1

Step-by-step explanation:

A pair of linear equations is consistent if it has a solution either a unique or infinitely many.

Given equations:

7

x

−

3

y

=

4

.....(1)

3

x

+

k

7

y

=

4

21

x

+

k

y

=

28

.....(2)

Here,

a

1

=

7

,

b

1

=

3

,

c

1

=

4

and

a

2

=

3

,

b

2

=

k

,

c

2

=

28

For given system ,

a

1

a

2

=

7

21

=

1

3

b

1

b

2

=

−

3

k

c

1

c

2

=

4

4

=

1

Clearly

a

1

a

2

≠

c

1

c

2

Hence, the pair of equations does not have infinitely many solution.

So, the system has a unique solution.

⇒

a

1

a

2

≠

b

1

b

2

⇒

1

3

≠

−

3

k

⇒

k

≠

−

9

Hope it's helpfull answer

Answer 2

Step-by-step explanation:

this is the correct answer