CBSE Class 12 Math 2011 Solved Paper

Question : 4

Total: 29

For what value of x, the matrix [

5−x	x+1
2	4

] is singular?

Solution:

Let A = [

5−x	x+1
2	4

]
It is given that the matrix A is singular, therefore |A| = 0
⇒ |

5−x	x+1
2	4

| = 0
⇒ 4(5 – x) – 2(x + 1) = 0
⇒ 20 – 4x – 2x – 2 = 0
⇒ -6x + 18 = 0
⇒ x =

−18

−6

= 3
Thus, when x = 3, the given matrix A is singular.

Go to Question:

Prev Question

Next Question