The answer is 6 because 21+9=30 and 30-6=24 and 24 is the number of students in the class.
Answer:
It is therefore a exponential function, as y increases with x.
Step-by-step explanation:
coordinates: ( 7 , 5 ) , ( 16 , 10 )
Slope: 
: 
: 
equation: y - y1 = m( x - x1 )
: 
: 
check if third coordinates matches:

......does not match, so its not linear.
3(-4+8) distribute the 3 to -4 and 8
(-12 + 24) add the terms
12
Answer: D
This result is true by De Moivre's theorem.
It’s up 2 over 3 i believe