The question you uploaded is asking to find the missing values to complete the equation. Here's the expression:

[ \text{[box]}(x + 2x) - \text{[box]}x = 2a + 5x ]

We need to fill in the two boxes on the left-hand side of the equation so that it matches the right-hand side.

Step-by-step solution:

1. Combine like terms inside the parentheses: $x + 2x = 3x$.
2. The expression on the left-hand side now becomes:
   [ \text{[box]}(3x) - \text{[box]}x ]
3. The right-hand side is given as $2a + 5x$. So we need the left-hand side to equal $2a + 5x$.
4. To match the $5x$, the second term in the left-hand side must be -5x. This suggests that the second box must be 5.
5. To balance the equation, the first box should result in $3x - 5x = -2x$, which means the first box must be -2.

Thus, the completed equation is:

$-2(3x) - 5x = 2a + 5x$

Would you like further details or have any questions about this solution? Here are five related questions:

1. What are the steps to combine like terms in algebraic expressions?
2. How do you distribute a coefficient across a sum inside parentheses?
3. Can you always solve for missing values in equations by comparing both sides?
4. What would happen if the equation had additional terms involving $a$?
5. How can you check if a solution is correct by substitution?

Tip: When solving algebraic equations, always simplify each side as much as possible before trying to balance or solve for unknowns.