Question

For what value of k, do the equations `3x - y + 8 = 0` and `6x - ky = -16` represent coincident lines ?
A. `(1)/(2)`
B. `-(1)/(2)`
C. 2
D. -2

Answer 1

Correct Answer - C
Condition for coincident lines is
`(a_(1))/(a_(2))=(b_(1))/(b_(2))=(c_(1))/(c_(2)) " " ` ...(i)
Given lines, `" " 3x-y+8 = 0`
and `" " 6x-ky+16 = 0`
Here, `" " a_(1) = 3, b_(1) = -1, c_(1) = 8`
and `" " a_(2) = 6, b_(2) = -k, c_(2) = 16`
From Eq. (i), `" " (3)/(6) = (-1)/(-k) = (8)/(16)`
`rArr " " (1)/(k) = (1)/(2)`
`:. " " k = 2`