If $ A = \begin{bmatrix} 1 & x \\ x^2 & 4y \end{bmatrix} $, $ B = \begin{bmatrix} -3 & 1 \\ 1 & 0 \end{bmatrix} $ and $ adj(A) + B = \begin{bmatrix} 1 & 0 \\ 0 & 1 \end{bmatrix} $ then find the value of `x` and `y`.