Given: kx + 3y = (k – 3) – eq 1

12x + ky = k – eq 2

Here,

a₁ = k, b₁ = 3, c₁ = k – 3

a₂ = 12, b₂ = k, c₂ = k

Given systems of equations has a unique solution

∴ ≠

≠

K² ≠36

k ≠ √36

∴ k ≠ ±6

∴ k ≠ 6 and k ≠ – 6

_{That is k can be any real number other than - 6 and 6}

∴ k is any real number other than 6 and - 6