Question

If the line l1 and l2 are parallel, then they have

Answer 1

Answer:

if lines l1 and l2 are parallel then their slopes are equal

m1=m2

happy learning

Answer 2

coplanar

Given lines are

L

1

:

−3

x+1

=

2

y−3

=

1

y+2

....(1)

L

2

,:

1

x

=

−3

y−7

=

2

z+7

....(2)

Now, a

1

a

2

+b

1

b

2

+c

1

c

2

=−3−6+2



=0

Hence, lines are not perpendicular.

Also,

a

2

a

1

=

b

2

b

1

=

c

2

c

1

does not holds.

So, the lines are not parallel.

Let's check now coplanarity.

Condition for coplanarity is

∣

∣

∣

∣

∣

∣

∣

∣

d

1

−c

1

a

1

b

1

d

2

−c

2

a

2

b

2

d

3

−c

3

a

3

b

3

∣

∣

∣

∣

∣

∣

∣

∣

=0

So consider, LHS=

∣

∣

∣

∣

∣

∣

∣

∣

1

−3

1

4

2

−3

−5

1

2

∣

∣

∣

∣

∣

∣

∣

∣

=7+28−35=0

Hence, the lines are coplanar.