Complete the table of products.
| First monomial → Second monomial ↓ | `2x` | `-5y` | `3x^2` | `-4xy` | `7x^2 y` | `–9x^2 y^2` |
| `2x ` | `4x^2` | . . . | . . . | . . . | . . . | . . . |
| `–5y` | . . . | . . . | `–15x^2 y` | . . . | . . . | . . . |
| `3x^2` | . . . | | . . . | . . . | . . . | . . . |
| `– 4xy` | . . . | . . . | . . . | . . . | . . . | . . . |
| `7x^2 y` | . . . | . . . | . . . | . . . | . . . | . . . |
| `–9x^2 y^2` | . . . | . . . | . . . | . . . | . . . | . . . |