Q34 of 256 Page 7

Write the value of .

We need to find the value of

Determinant of 2 × 2 matrix is found as,

So,

Rearranging,

Using the algebraic identity,

(x + y)(x – y) = x² – y²

Here, i is iota, an imaginary number.

Note that,

i² = -1

So,

Thus,

A matrix of order 3 × 3 has determinant 2. What is the value of |A(3I)|, where I is the identity matrix of order 3 × 3.

If A and B are square matrices of order 3 such that |A| = -1, |B| = 3, then find the value of |3AB|.

Write the cofactor of a₁₂ in the matrix .

If find x.