Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section A

Chapter

Determinants

Question:

If $\left|\begin{array}{cc}2 & 3-x \\ x & 1\end{array}\right|=0$, then the values of x are:

Options:

1 and 3

1 and 2

2 and 3

3 and 0

Correct Answer:

1 and 2

Explanation:

$\left|\begin{array}{cc}2 & 3-x \\ x & 1\end{array}\right|=0$

⇒  2 × 1 - (3 - x)(x)

⇒  2 - 3x + x2 = 0

⇒  x2 - 3x + 2 = 0

⇒  x2 - 2x - x + 2 = 0

⇒  x(x - 2) - 1(x - 2) = 0

⇒  (x - 1) (x - 2) = 0

⇒  x = 1, 2