The given expression is:

$(x + 2x) \cdot (x - 1)$

Step 1: Simplify the terms inside the parentheses

In the first parentheses, combine like terms: $x + 2x = 3x$

So the expression becomes: $(3x) \cdot (x - 1)$

Step 2: Apply the distributive property

Distribute $3x$ to each term inside $(x - 1)$: $3x \cdot x - 3x \cdot 1$

Step 3: Simplify each term

$3x \cdot x = 3x^2 \quad \text{and} \quad 3x \cdot 1 = 3x$

Thus, the expression simplifies to: $3x^2 - 3x$

Final Answer:

$3x^2 - 3x$

Let me know if you'd like more details or further assistance! 😊

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Related Questions:

1. What is the derivative of $3x^2 - 3x$?
2. How would the result change if the second factor were $x + 1$ instead of $x - 1$?
3. Can you factorize the final result $3x^2 - 3x$?
4. How does this expression behave graphically for values of $x$?
5. Can you evaluate $3x^2 - 3x$ for specific values like $x = 2$ or $x = -1$?

Tip:

When simplifying algebraic expressions, always combine like terms before distributing or factoring.