Question
Find the variable for the following 3x3 matrix.
|x 3 -1
2 1 -2
4 1 x|
Note: This entire matrix =10
|x 3 -1
2 1 -2
4 1 x|
Note: This entire matrix =10
Answers
Jenny
I need help with this ASAP. Thanks so much!
Reiny
Did you mean the determinant of the matrix is 10 ?
Jenny
Yes.
Reiny
I don't know what method you have learned to find the determinant, but I get
x^2 - 4x - 22 = 10
x^2 - 4x - 32 = 0
(x-8)(x+4) = 0
x=8 or x=-4
x^2 - 4x - 22 = 10
x^2 - 4x - 32 = 0
(x-8)(x+4) = 0
x=8 or x=-4