The cost of a hamburger is $2.50. each additional hamburger cost $2.00. sully wrote this explicit rule to explain the sequence of costs: f(n) = 2 + 2.5(n-1). using the rule, he found the cost of 12 hamburgers to be 29.50. is this number correct?

Yes, the number is correct.

Step-by-step explanation:

The cost of a hamburger is $2.50.

Each additional hamburger cost $2.00.

Sully wrote this explicit rule to explain the sequence of costs:

Using the rule, he found the cost of 12 hamburgers to be 29.50.

Lets check by putting n = 12.

=

=  

= $29.50

So, yes Sully is correct.

i think the answer is a.( -3, -1 )