Question

if X-2y+7=0 and 2x-ky+8=0 line are parallel then k is a)-4 b)4 c)8 d)7​

Answer 1

Answer:

If X-2y+7=0 and 2x-ky+8=0 line are parallel then k is  (b) 4

Step-by-step explanation:

The given equations are of the form

$a_1x+b_1y+c_1=0------------------(1)$

and

$a_2x+b_2y+c_2=0------------------(2)$

Where

                $a_1=1 , b_1=-2 , c_1=7\\ \\ a_2=2, b_2=-k , c_2=8$

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

The condition for which is

                                            $\frac{a_1}{a_2} =\frac{b_1}{b_2} =\frac{c_1}{c_2} \\ \\ \frac{1}{2} =\frac{-2}{-k} =\frac{7}{8}\\ \\ k=4$