To find the equation that determines the number of balloons Alexa popped, we can start from the information given:
- Krista popped 5 balloons.
- Together, Krista and Alexa popped a total of 13 balloons.
We can express the total they popped with the equation:
\[ n + 5 = 13 \]
Where:
- \( n \) is the number of balloons Alexa popped.
To solve for \( n \):
\[ n + 5 = 13 \] Subtracting 5 from both sides:
\[ n = 13 - 5 \] \[ n = 8 \]
Therefore, Alexa popped 8 balloons.
The correct response is: n + 5 = 13; Alexa popped 8 balloons.