Question

find the Value of k when lines x+y+1=0 and 2x+ky+2=0 are coincident​

Answer 1

Answer:

The given equations are of the form

a

1

x+b

1

y+c

1

=0

and a

2

x+b

2

y+c

2

=0

where a

1

=1,b

1

=2,c

1

=7

and a

2

=2,b

2

=k,c

2

=14

The given equations will represent coincident lines if they have infinitely many solutions.

The condition for which is

a

2

a

1

=

b

2

b

1

=

c

2

c

1

⇒

2

1

=

k

2

=

14

7

⇒k=4

Hence, the given system of equations will represent coincident lines, if k=4.