Answer: D . 
Step-by-step explanation:
Given : Jenny studied the characteristics of two species of bacteria. The number of bacteria of species A, A(t), after t hours is represented by the function,

The number of bacteria of species B, B(t), after t hours is represented by the function, 
Then, the difference in the number of bacteria, N(t), of both the species after t hours will be :-

Hence, the correct answer should be : D . 
Question one:A
Question 2: C
Answer:
14.45
Step-by-step explanation:
x^2+(7.1)^2=(16.1)^2
×^2+50.41=259.21
x^2=208.8
sqrt(x^2)=sqrt(208.8)
x=14.45
check.
14.45^2 + 7.1^2 = 16.1^2
Answer: 20. 4, 3, 2, 1...
21. 17....
Step-by-step explanation:
Answer:
What expression?
Step-by-step explanation: