The expression you provided is $x(x + 1)$.

To expand this expression, you multiply $x$ by each term inside the parentheses:

$x(x + 1) = x \cdot x + x \cdot 1 = x^2 + x$

So, the expanded form is $\boxed{x^2 + x}$.

Would you like further details or have any questions?

Here are 5 related questions:

1. How do you factor the expression $x^2 + x$?
2. What is the value of $x(x+1)$ when $x = 2$?
3. How does the distributive property apply to expressions like $x(x+1)$?
4. Can you simplify the expression $x(x + 2)$ using the same method?
5. How do you solve the equation $x(x + 1) = 0$?

Tip: When expanding expressions, always distribute each term outside the parentheses to every term inside.