Target Exam

CUET

Subject

-- Mathematics - Section A

Chapter

Determinants

Question:

The system of equation $2x + λy = 8, λx+8y = 3$ has a unique solution if the value of $λ$ is (are):

Options:

$λ≠±4$

$λ= 4$

$λ=-4$

$λ$ is any real number

Correct Answer:

$λ≠±4$

Explanation:

The correct answer is Option (1) → $λ≠±4$

Given system:

$2x + \lambda y = 8$

$\lambda x + 8y = 3$

For a unique solution, determinant of coefficients ≠ 0:

$\begin{vmatrix}2 & \lambda \\ \lambda & 8\end{vmatrix} \ne 0$

$\Rightarrow 16 - \lambda^{2} \ne 0$

$\Rightarrow \lambda^{2} \ne 16$

$\Rightarrow \lambda \ne \pm 4$

Unique solution for $\lambda \ne \pm 4$