Find the value of 'k' for which the system of equations 4x + 6y = 7 and 6x + (k + 4)y - 21 = 0 has a unique solution.
Show answer & explanation
Correct answer: B
Explanation
The correct answer is Option 2 i.e. k ≠ 5.
4x + 6y = 7 and 6x + (k + 4)y - 21 = 0
We know that,
For unique solution = a1/a2 ≠ b1/b2
⇒ 4/6 ≠ 6/(k + 4)
⇒ 1/3 ≠ 3/(k + 4)
⇒ k + 4 ≠ 9
⇒ k ≠ 5