The given problem states:

"The quotient of a number $x$ and $-1.5$ is 21."

Step 1: Write the equation

The word problem can be translated into the equation: $\frac{x}{-1.5} = 21$

Step 2: Solve for $x$

To solve for $x$, multiply both sides of the equation by $-1.5$: $x = 21 \times -1.5$

Simplify: $x = -31.5$

Final Answer:

• Equation: $\frac{x}{-1.5} = 21$
• Solution: $x = -31.5$

Would you like a detailed breakdown of the steps? Let me know if you have further questions!

Here are some related questions to explore:

1. How do you interpret "quotient" in a math problem?
2. How would the equation change if the problem involved addition instead of division?
3. What steps ensure accuracy when working with negative numbers?
4. How can this concept be applied to real-world problems?
5. What happens if the divisor ($-1.5$) changes to a positive number?

Tip: Always double-check your calculations, especially when multiplying or dividing with negative numbers!