Answer:
The linear equation is y = 10 x
Explanation:
Hi, to answer this question we have to analyze the information given: 
- Rise rate = 10 ft per second 
For each unit of time, we get ten units of height. 
So, the linear equation is 
y = 10 x 
Where "y" is the height of the balloon after "x" seconds. 
If we replace the variable x for a value we obtain the height. 
For example, after 1 second: 
y = 10 ft / sec x 1 sec 
y = 10 feet 
Feel free to ask for more if needed or if you did not understand something.