Helps me solve this problem please

Use the quadratic function to predict f(x) if x equals 8. f(x) = 25x2 − 28x + 585

Janie has $3. she earns $1.20 for each chore she does and can do fractions of chores. she wants to earn enough money to buy a cd for $13.50.

Which function represents the sequence? f(n)=n+3 f(n)=7n−4 f(n)=3n+7 f(n)=n+7