The problem asks to select the expressions that are equivalent to $5x + 5x$.

1. Problem Description

The problem asks to select the expressions that are equivalent to $5x + 5x$.

2. Solution Steps

First, simplify the given expression:

$5x + 5x = (5+5)x = 10x$

Now, we need to check which of the given options are equivalent to $10x$.

- Option 1: $11x$. This is not equal to $10x$.

- Option 2: $x + 10$. This is not equal to $10x$.

- Option 3: $x + 4x + 5x = (1+4+5)x = 10x$. This is equal to $10x$.

- Option 4: $x^{10}$. This is not equal to $10x$.

Therefore, only the expression $x + 4x + 5x$ is equivalent to $5x + 5x$.

3. Final Answer

$x + 4x + 5x$