I don't know where I should be going when solving for an unknown in a matrix.

My question is "Find the value of x for which A does not have an inverse".

A=

(1 3)

(x 2)

The statement 'A does not have an inverse' throws me off - does this mean there is no inverse? I know how to find the inverse of a matrix, but don't know how to solve for x. Is finding the inverse the goal of the exercise?

Cheers