Question

Nancy has $400 and spends $20 each week.
Which function rule describes the situation?

Answer 1

Since Nancy has $400 dollars ans spends $20 each week. The word "Has" and "Spends" indicates the positive and the negative. so if we write the function rule saying f(d) then we should use it to our equation saying.

Answer:

f(d)=400-20d

Hope this helps! :)