Solve the matrix equation `[x^2,y^2]-3[x,2y]=[-2, 9]`

Explanation

To solve the matrix equation \([x^2, y^2] - 3[x, 2y] = [-2, 9]\), we will break it down into two separate equations for \(x\) and \(y\).

### Step 1: Set up the equations
From the matrix equation, we can separate it into two components:
1. For the first element:
\[ x^2 - 3x = -2 \]
...