Find the value of k so that the pair of equations x + 2y = 5 and 3x + ky + 15 = 0

Find the value(s) of k so that the pair of equations x + 2y = 5 and 3x + ky + 15 = 0 has a unique solution.

Answer

For unique solution

1/3 ≠ 2/k

⇒ k ≠ 6