The expression you provided is:

$5x(x)$

This can be simplified by multiplying the terms together. Since $x$ is multiplied by itself, this is effectively:

$5x^2$

So, the simplified result is:

$5x^2$

Would you like further explanation or have any additional questions?

Here are some related questions for further exploration:

1. What is the value of $5x^2$ when $x = 2$?
2. How do you factor the expression $5x^2$?
3. What are the properties of quadratic functions like $5x^2$?
4. How can you solve an equation where $5x^2 = 25$?
5. What happens to the graph of $y = 5x^2$ as $x$ increases?

Tip: When simplifying expressions like $5x(x)$, always look for opportunities to combine like terms or apply exponent rules, such as $x \times x = x^2$.