Question

8. Find values of k such that the equations -x + 3y = 0, and -3x + ky - 9 = 0, represents
coincident lines.
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Answer 1

Answer : 9

Step:

Here,

-x + 3y = 0 _______( 1)

and, -3x + ky -9 = 0__________(2)

So, a¹ = -1, b¹ = 3 and c¹ = 0

and, a² = -3, b² = k and c² = -9.

Since, it represents a coincident lines,

= a¹/a² = b¹/b² = c¹) c²

Here arises two cases:

Case 1 : a¹/a² = b¹/b²

• -1/-3 = 3/k

(Now we do cross- multiplication)

• -k = -9.
• k = 9..

Hence, the value of k = 9.