1. **State the problem:** Simplify the expression $12xy - 6x + 18yx^2 - 8x - 4xy - 23yx^2$. 2. **Identify like terms:** - Terms with $xy$: $12xy$ and $-4xy$ - Terms with $x$: $-6x$ and $-8x$ - Terms with $yx^2$: $18yx^2$ and $-23yx^2$ 3. **Combine like terms:** - $12xy - 4xy = 8xy$ - $-6x - 8x = -14x$ - $18yx^2 - 23yx^2 = -5yx^2$ 4. **Write the simplified expression:** $$8xy - 14x - 5yx^2$$ 5. **Final answer:** The simplified form of the expression is $8xy - 14x - 5yx^2$.