1. The problem involves simplifying and understanding algebraic expressions with variables $X1$, $X2$, $X3$, and $X4$ combined with fractions. 2. The expressions given are: $$\frac{3X}{8} + \frac{X^2}{8} + \frac{X^3}{8} + \frac{X^4}{8}$$ $$\frac{X1}{10} + \frac{X2}{5} + \frac{X3}{5} + \frac{X4}{2}$$ $$\frac{X1}{5} + \frac{X2}{5} + \frac{X3}{4} + \frac{X4}{4}$$ $$\frac{X1}{3} + \frac{X3}{3} + \frac{X4}{3}$$ 3. To simplify or combine these expressions, we use the rule of adding fractions: find a common denominator and combine numerators. 4. For example, to add $\frac{X1}{10} + \frac{X2}{5}$, find the least common denominator (LCD) which is 10: $$\frac{X1}{10} + \frac{X2}{5} = \frac{X1}{10} + \frac{\cancel{2}X2}{\cancel{2}10} = \frac{X1}{10} + \frac{2X2}{10} = \frac{X1 + 2X2}{10}$$ 5. Similarly, for $\frac{X3}{5} + \frac{X4}{2}$, LCD is 10: $$\frac{\cancel{2}X3}{\cancel{2}10} + \frac{5X4}{5\times 2} = \frac{2X3}{10} + \frac{5X4}{10} = \frac{2X3 + 5X4}{10}$$ 6. Combining all terms in the second expression: $$\frac{X1 + 2X2 + 2X3 + 5X4}{10}$$ 7. The same approach applies to the other expressions by finding their LCDs and combining terms. 8. This method helps in simplifying and comparing algebraic expressions with fractional coefficients. Final simplified form for the second expression is: $$\frac{X1 + 2X2 + 2X3 + 5X4}{10}$$