Someone please help me! I need this done ASAP

Answer: ill try to do #3 for you
A. money= dependent (depends on days)
days= independent
B. im guessing its this: m=250d
C. $250x 10 days= $2,500 he will need to save
also #4 is y-2x-2
if this is all correct could u mark my answer brainliest if you want to thanks!