1. **State the problem:** Determine the sign of the expression $$\frac{x}{y} \cdot 7y^3$$ given that $$x < 0$$ and $$y > 0$$.
2. **Rewrite the expression:**
$$\frac{x}{y} \cdot 7y^3 = 7x \cdot \frac{y^3}{y} = 7x y^{3-1} = 7x y^2$$
3. **Analyze the signs:**
- Since $$x < 0$$, $$x$$ is negative.
- Since $$y > 0$$, $$y^2 = y \cdot y$$ is positive because the square of a positive number is positive.
- The constant 7 is positive.
4. **Combine the signs:**
- The product $$7x y^2$$ is positive \(7\) times negative \(x\) times positive \(y^2\).
- Multiplying positive \(7\) and positive \(y^2\) gives positive.
- Multiplying positive result by negative \(x\) gives negative.
5. **Conclusion:** The expression $$\frac{x}{y} \cdot 7y^3$$ is negative under the given conditions.
**Final answer:** (B) Negative
Sign Expression 3F1Dd7
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.