The image shows an equation that needs to be solved. The equation given is:

$x + 9 = 12$

To solve for $x$, subtract 9 from both sides of the equation:

$x + 9 - 9 = 12 - 9$

This simplifies to:

$x = 3$

So, the correct answer is $x = 3$.

Would you like more details or have any questions?

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Here are 5 related questions:

1. What is the process for solving a two-step linear equation?
2. How can you check if the solution to an equation is correct?
3. What happens when both sides of an equation are multiplied by the same number?
4. Can you solve $2x + 5 = 15$ for $x$?
5. What is the difference between a linear equation and a quadratic equation?

Tip: Always double-check your calculations by substituting the solution back into the original equation to ensure accuracy.