For f(x) = 2x+3 which represents f(x) when x= 6?

A.16
B.20
C.28
D.96

Dylan and dusty plan to take weekly surfing lessons together. if the 2-hour lessons are $20 per person and they plan to spend $100 each on new surfboards, what is the maximum number of lessons the two can take if the total amount spent for lessons and surfboards is at most $480?

Anyone know? will mark brainliest if correct!

Which expression is equivalent to 8(k + m) − 15(2k + 5m)?