For what value of k, do the equations 3x - y + 8 = 0 and 6x - ky + 16 = 0 represent coincident lines?


Condition for coincident lines is -

a1/a2 = b1/b2 = c1/c2 …(i)


Given lines, 3x - y + 8 = 0


and 6x - ky + 16 = 0;


Comparing with ax + by + c = 0;


Here, a1 = 3, b1 = - 1, c1 = 8; a2 = 6, b2 = - k, c2 = 16;


and


From Eq. (i),



So, k = 2

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