Starting with the equation $x = 10$, if we add 9 to both sides, the equation becomes:

$x + 9 = 10 + 9$

Simplifying the right-hand side:

$x + 9 = 19$

This is the new equation.

Would you like more details or have any questions?

Here are 5 related questions to deepen your understanding:

1. What happens if you subtract 5 from both sides of $x + 9 = 19$?
2. Can you solve for $x$ in $x + 9 = 19$?
3. What would happen if you multiplied both sides of $x = 10$ by 3 instead of adding 9?
4. How would you solve $2x = 10$?
5. What is the result of dividing both sides of $x + 9 = 19$ by 2?

Tip: Always perform the same operation on both sides of an equation to maintain its equality.