Solve the following equation involving a determinant

det x (x+2)

9 2x = 0

I did x * 2x - 9(x+2)

It came out to 2x^2 - 9x - 18 = 0

Do I have to do anything else like a quadratic equation? I went to a math tutor and he wasn't sure. I scanned the problem and it's number 11.

http://pic20.picturetrail.com/VOL137.../392720959.jpg