Answer:
{1}
Step-by-step explanation:
We find determinant for the given matrix and set it equal to -1
To find determinant we apply formula
[tex]|A| = a_{11}(a_{22}a_{33} − a_{32}a_{23}) - a_{12}(a_{21}a_{33} − a_{31}a_{23})+a_{13}(a_{21}a_{32} - a_{31}a_{22})[/tex]
[tex]|A| = x(1x - 2) - 0(7-7) + 0(14-7x) [/tex]
|A| = x^2 - 2x
Now we set the determinant = -1
[tex]x^2 - 2x=-1[/tex]
Add 1 on both sides
[tex]x^2 - 2x + 1=0[/tex]
Now factor it
(x-1)(x-1) = 0
Set each factor =0 and solve for x
x- 1=0 so x=1
