Question:

If $ \left| \begin{matrix} x+7 & 5 \\ x+-3 & 3 \\ \end{matrix} \right|=26, $ then x is equal to

Updated On: Jun 23, 2024
  • $ 1 $
  • $ 3 $
  • $ 5 $
  • $ 7 $
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The Correct Option is C

Solution and Explanation

Given, $ \left| \begin{matrix} x+7 & 5 \\ x-3 & 3 \\ \end{matrix} \right|=26 $
$ \Rightarrow $ $ 3(x+7)-5(x-3)=26 $
$ \Rightarrow $ $ 3x+21-5x+15=26 $
$ \Rightarrow $ $ -2x+36=26 $
$ \Rightarrow $ $ 2x=10 $
$ \Rightarrow $ $ x=5 $
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Concepts Used:

Matrices

Matrix:

A matrix is a rectangular array of numbers, variables, symbols, or expressions that are defined for the operations like subtraction, addition, and multiplications. The size of a matrix is determined by the number of rows and columns in the matrix.

The basic operations that can be performed on matrices are:

  1. Addition of Matrices - The addition of matrices addition can only be possible if the number of rows and columns of both the matrices are the same.
  2. Subtraction of Matrices - Matrices subtraction is also possible only if the number of rows and columns of both the matrices are the same.
  3. Scalar Multiplication - The product of a matrix A with any number 'c' is obtained by multiplying every entry of the matrix A by c, is called scalar multiplication. 
  4. Multiplication of Matrices - Matrices multiplication is defined only if the number of columns in the first matrix and rows in the second matrix are equal. 
  5. Transpose of Matrices - Interchanging of rows and columns is known as the transpose of matrices.