Skip to main content
Back to Matrices & Determinants
JEE Main 2019
Matrices & Determinants
Matrices and Determinants
Medium

Question

If \left| {\matrix{ {x - 4} & {2x} & {2x} \cr {2x} & {x - 4} & {2x} \cr {2x} & {2x} & {x - 4} \cr } } \right| = \left( {A + Bx} \right){\left( {x - A} \right)^2} then the ordered pair (A, B) is equal to :

Options

Solution

Key Concept: Properties of Determinants and Algebraic Comparison

This problem requires us to evaluate a 3×33 \times 3 determinant using elementary row and column operations. The goal is to simplify the determinant into a factored form and then compare it with a given algebraic expression to determine the values of constants AA and BB. The key properties of determinants we will use are:

  1. Column/Row Operations: Adding a multiple of one column (or row) to another column (or row) does not change the value of the determinant. This is useful for creating zeros or common factors.
  2. Factoring: A common factor from any single row or column can be taken out of the determinant.
  3. Triangular Determinant: The determinant of a triangular

Practice More Matrices & Determinants Questions

View All Questions