How to Solve an Equation Involving a Determinant?

[rowdy3]

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/VOL1370/5671323/23539305/392720959.jpg

 

[jambaugh]

No. You simply solve the quadratic and check your solutions within the original equation.