Me with this i have absolutely no idea what the answer is!

A. Her expenses are $25 per week.  

Step-by-step explanation:

Using a linear function f(x) = mx + b, m= slope and b = y-intercept or initial value.  With the values of the given function:  E(x) = 7x - 25, we can determine that the overall earnings (E(x)) is based on a profit of $7 per door ('x') and that if Jessica is subtracting $25 from her earnings, that this must be the cost per week for her expenses.  So, she would need to knock on a minimum of 4 doors each week in order to make a profit.

it would be 6xy and -16xy.

question: how many people can she serve?

answer: she can serve 16.66666667 people. so she can only give 16 people a complete serving.

question: does she have enough ice cream for her guests?

answer: no. explanation: she only has enough for 16 people to have a full serving. however, she can give a 17th person a partial serving.