MHT CET 2018 Math Solved Paper

(c) 5x + y - 1 = 0 coincides
5x2 + xy - kx - 2y + 2 = 0
a = 5,b = 0, h =

1

2

, g = −

k

2

, f = -1, c = 2
If the above equation represents a pair of straight lines, then
|

a	h	g
h	b	f
g	f	c

| ⇒ |

5	1 2	− k 2
1 2	0	−1
− k 2	−1	2

|
∴ 5(0 - 1) -

1

2

(1−

k

2

)−

k

2

(

−1

2

−0) = 0
∴ −5−

1

2

+

k

4

+

k

4

= 0 ⇒

k

2

=

11

2

⇒ k = 11