the question says that the samples included 100 people each, so it's just 100 multiplied by the amount of samples:
7×100=700
Answer: 
Concept:
In a function f(x), it represents a function in terms of x or for x. Therefore, to find the values in the function, substitute values within the parenthesis to solve.
Solve:
<u>Given information</u>

<u>Need to find</u>

<u>Substitute (x + 4) to the position of x</u>

<u>Distributive property on the numerator</u>

<u>Combine like terms</u>


Hope this helps!! :)
Please let me know if you have any questions
Answer:
the answer is 2 1/3 or There is 2\frack{11}{14}\ cups needed to make every dozen of muffins.
Step-by-step explanation:
Hope this helps:)