1. The problem involves simplifying expressions with square roots and variables: $$4.5\sqrt{3524} - 3xyx^4 - 4hy$$ and $$5\sqrt{8xy} + xhy^3$$. 2. Recall the properties of square roots: $$\sqrt{a} \times \sqrt{b} = \sqrt{ab}$$ and $$\sqrt{a^2} = |a|$$. 3. Simplify each term step-by-step. 4. For $$4.5\sqrt{3524}$$, factor 3524 to simplify the root if possible. 5. For $$-3xyx^4$$, combine like terms: $$-3x^{1+4}y = -3x^5y$$. 6. The term $$-4hy$$ remains as is. 7. For $$5\sqrt{8xy}$$, simplify inside the root: $$8 = 4 \times 2$$, so $$5\sqrt{4 \times 2xy} = 5 \times 2 \sqrt{2xy} = 10\sqrt{2xy}$$. 8. The term $$xhy^3$$ remains as is. 9. Final simplified expressions: $$4.5\sqrt{3524} - 3x^5y - 4hy$$ and $$10\sqrt{2xy} + xhy^3$$. Note: Without further instructions, these are the simplified forms.