Question

College algebra ! Help ASAP !!!

Answer 1

{1}

Explanation:

We find determinant for the given matrix and set it equal to -1

To find determinant we apply formula

`|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))`

`|A| = x(1x - 2) - 0(7-7) + 0(14-7x)`

|A| = x^2 - 2x

Now we set the determinant = -1

`x^2 - 2x=-1`

Add 1 on both sides

`x^2 - 2x + 1=0`

Now factor it

(x-1)(x-1) = 0

Set each factor =0 and solve for x

x- 1=0 so x=1